Which phone should be best suited within the range of 25,000.

The Rs. 25000 price bracket is quite good when it comes to the smartphone currently available. Some of the choices that may suit you include:

LeEco Le max 2
LeEco has been quite a name to reckon with after a series of launches. The smartphone has a display size of 5.7 inch at a resolution of 1440 x 2560 pixels. The device is powered by Dual-core 2.1 GHz Kryo & dual-core 1.6GHz Kryo Snapdragon 820. The internal memory you have on board is 32 GB. Unfortunately there is no expandable memory option. It offers you a whopping 4 GB RAM that should help you work with your phone super fast. The rear camera resolution on the device is 21 MP while the front snapper reads 8 MP. Le Max 2 runs on Android Marshmallow 6.0 and offers you dual SIM functionality along with 4 G compatibility. The battery capacity reads 3100 mAh.
You can buy the phone at Rs. 18000.

Xiaomi Mi5
The phone is powered by Dual-core 1.8 GHz Kryo & dual-core 1.36 GHz Kryo Snapdragon 820. The 5.15 inch display offers a full HD resolution of 1920 x01080. The internal storage is 32 GB with no expandable memory option. The 3 GB RAM is considerably good for effective multitasking. The rear camera resolution is 16 GB with f/2.0 aperture and Optical image stabilisation. The front camera reads 4 MP. The Mi5 runs on Android Marshmallow. I expect it to get Android Nougat update. The battery capacity of the device is an impressive 3000 mAh.
The phone is priced at Rs. 23000 which may appear little heavy compared to the competitors with the same spec sheet.

Moto Z Play
The smartphone is powered by Snapdragon 625 Octa-core 2.0 GHz Cortex-A53. You get a Super AMOLED display at full HD resolution of 1920 x 1080 pixels. The screen size reads 5.5 inch. The internal storage capacity of the device is 32 GB which can be expanded further. You get 3 GB of RAM capacity. The phone runs on Android 6.0 Marshmallow. The rear camera has a resolution of 16 MP while the front cmaera resolution reads 5 MP. Battery capacity of Moto Z Play is 3150 mAh.
The smartphone costs Rs. 24990.

Lenovo Z2 Plus
The smartphone is powered by Snapdragon 820 Quad-core. The phone has 5 inch IPS display at a full HD resolution of 1920 x 1080 pixels. Z2 Plus is available in two memory variants of 32 and 6
4 GB. The 32 GB variant has a RAM of 3 GB while the 64 GB variant comes with a 4 GB RAM. The phone offers you expandable memory option. The rear camera has a resolution of 13 MP while the front camera is of 8 MP resolution. The battery capacity reads 3500 mAh. The phone runs on the Android Marshmallow OS.
You can buy it at Rs. 17999 and Rs. 19999 for the 32 GB and 64 GB variants respectively.

Asus Zenfone 3
Powered by Snapdragon 625 octa-core 2.GHz, Zenfone 3 runs on Android Marshmallow 6.0. The 5.2 inch screen has a resolution of 1920 x 1080 pixels. The internal memory of the smartphone is 32 GB. You can expand the memory further using microSD card. Zenfone 3 has a RAM capacity of 3 GB. The rear camera on the device is of 16 MP resolution while the front camera has a resolution of 8 MP. The battery capacity of the device is 2650 mAh.
The Asus Zenfone 3 will cost you Rs. 22000.

For your existing device, you may not get any higher price than Rs. 4000 to 5000. I would advise you to sell the device on sites like Quickr or OLX where you may get a good price. Better still, you can ask your friends and colleagues if they are interested.

It is good to have a budget of 25,000 for spending for the best Smartphone. Already you are an Android operating system user. From my point of view, I suggest you to stay with the Android operating system. Android still remains to be the best in performance and user friendliness. The present price of your existing device Samsung Galaxy E7 is Rs. 15,900. The price may vary from site to site. If you try to sell this mobile, it could be around lowest cost in online. Even if you exchange in shop, they will also provide you the lowest cost. My advice is, you can sell this device to your friends or known persons in an affordable price. This could increase the cost of your mobile to some extent.

Some of the best Smartphones which suites for your budget of Rs. 25,000 are listed below:

OnePlus 2
OnePlus is the leading model in the market. It provides better flexibility for the user. This model runs in Android 6.0 marshmallow operating system. The connectivity comes with 4G and also dual sim functionalities. It has a better display size of 5.5 inches with the IPS performance. The display resolution for the device is 1080 x 1920 pixels. In this model there is no external slot for the storage space but the internal storage area is vast. It brings up 64GB storage area for the users. This device is powered by Snapdragon 810 Quad core processor. The RAM size of the device is 4GB. The rear camera functions with 13MP and front camera functions with 5MP. The battery capacity for the device is 3,300 mAh. This device costs for Rs. 19,999.

LeEco Le Max 2
LeEco is currently one of the top trending model selling in Flipkart. This brand started their debut in Flipkart and reached their success and desired position in the market. This device is powered by Kryo Snapdragon 820. This device has 4GB RAM for boosting memory. The display size comes with 5.7 inches and the resolution it has 1440 x 2560 pixels. This device comes with 4G connectivity with dual sim functionality. There is no external storage slot in the device. The internal storage space has 32GB. The rear camera comes with 21MP and front camera comes with 8MP. The battery capacity for the mobile is 3,100 mAh. This device runs in Android 6.0 marshmallow operating system. The price for the device is Rs. 17,990.

Samsung Galaxy A7 – 2016
Samsung brand is one of the best brands in Smartphone industry. This brand gives toughest fight in the market to create revolution in the Android world. This device comes with dual sim with the connectivities of 3G and 4G network bands. The display size of this model is 5.5 inches. The display resolution of this device is 1920 x 1080 pixels. This device is powered by Octa core processor with 1.6Ghz. The rear camera functions with 13MP and front camera functions with 5MP. This device supports OTG. The internal storage for the device is 16GB and the external storage comes with 128GB as expandable. The RAM size is 3GB. The battery capacity for the mobile is 3,300 mAh. It is not removable type. This device runs in Android 6.0 marshmallow operating system. The price for the device is Rs. 25,450 which is little expensive from your budget in border line.

Xiaomi Mi 5
Xiaomi is a brand which holds the 'nothing is impossible' mission for their users. The 'MI' stands for Mobile Internet or Mission Impossible by the Xiaomi. They make better quality of technology which can be accessible to everyone. This model runs in Android 6.0 marshmallow operating system. It has the connectivity of 4G network with dual sim functions. This device is powered by Kryo Snapdragon 820. The display size is 5.15 inches and 1920 x 1080 pixels of resolution. The RAM size is 3GB. The internal storage has 32GB space but there is no storage for external memory. The rear camera comes with 16MP and front camera comes with 4MP. The battery is non-removable and the capacity of it is 3,000 mAh. The price of the device is Rs. 22,990.

Lenova Z2 Plus
This device is powered by Kryo Snapdragon 820. It has dual sim with 4G connectivity. It has LCD display with 5 inches of size. The resolution of the display is 1080 x 1920 pixels. The rear camera comes with 13MP and front camera comes with 8MP. There is no external slot in this mobile. This device runs in Android 6.0 marshmallow operating system. The battery storage capacity of this device is 3,500 mAh. For 3GB of RAM size, the device comes with 32GB of internal storage space. It was priced for Rs. 14,990. For 4GB of RAM size, the device comes with 64GB of internal storage space. It was priced for Rs. 17,490.

Here are some of the answers to your questions and also recommendations for the mobile phones that come under Rs.25000

Between the Windows, Apple and Android phone, the best option is to go with Android. The reason being it is not only a value for money, but it's also easy to troubleshoot, and is secure with more options that beats Apple and Windows.

As for the value for your phone which is used for 1 year, I suggest checking out sahiprice website. They do some valuation based on the questionnaire. And you can decide the price based on that.

Some of the phone under 25K for your requirement are as follows.

Xiaomi Mi Max

This is one of the premium phone under 25k. The best part about the Mi phone is the camera. It comes in multiple storage variety upto 128GB. It has 16MP primary camera and 5MP secondary. It has 6.44 inch display with IPS touchscreen. It has Android Marshmallow installed. In terms of value for money, this is the phone to choose from. You can find it on Amazon for 19,999 Rs. Check it out here : http://www.amazon.in/Xiaomi-Mi-Max-Prime-128GB/dp/B01DDP7MC2/

Lenovo Z2 Plus

This is another device that is gaining a lot of attention. In fact most of the people who want 13MP front end camera and 8MP back end camera. It has Qualcomm Snapdragon 820 processor and 4GB RAM. So in terms of performance the device is really good. It is priced at 17,499 Rs on Amazon. You can check it here: http://www.amazon.in/Lenovo-Z2-Plus-Black-64GB/dp/B01FM7HV34/

Vivo V5

Lot of good reviews about this mobile. And there are lot of people who liked the camera of this phone. So for this price range with good camera. I think this is worth taking a look at. It has 20MP and 13 MP camera for front and backend respectively. With 5.5. inch display and 4GB RAM. 1.5GHz MediaTek MT6750 octa core processor. And 3000mAH lithium-ion battery gives some good performance. It is priced at 17,145Rs on Amazon. You can find it here: http://www.amazon.in/VIVO-V5-Vivo-Crown-Gold/dp/B01N7AG0AX

Leeco Max 2 X821

Leeco has launched some good phones last two years. And Max 2 is another one of those good devices. 5.7 inch display with 4GB RAM and Qualcomm Snapdragon 820 Processor. You may find that 21MP Primary Camera can take some good shot. Also the secondary camera is good too with 8MP capacity. 3100 mAh Li-Ion Polymer Battery gives some good performance. It is priced at 17,697 Rs. on Amazon. You can get it on : http://www.amazon.in/Leeco-Max-2-X821-Grey/dp/B01MFDMCM7

Oppo F1S

Oppo F1S has managed to get some good review in short time. It has 13mp primary camera and in terms of picture quality it surely is worth mentioning. Though the device is still at the 5.1 android version, you may find that there is not difference in performance. It has 3075mAH lithium-ion battery with 28.5 hours talktime. With 1.5GHz 64-bit Octa core processor and 4GB RAM the device surely has a good performance. It is priced at : 18,580 Rs on Amazon.You can get it on : http://www.amazon.in/Oppo-A1601-F1S-Gold-64GB/dp/B01NCEG4UD/

There are many other devices under 25k. But these are the ones which are worth taking a look at for their performance and cameras. You may also want to take a look at some Windows phone under this price range if you like Windows phones.

Here is a list of five best phones that would come under your budget of Rs.25000

1. OnePlus 2
Framed within a premium stainless steel body the phone is beautifully designed with a multi-touch IPS 5.5 inches screen protected by a Corning Gorilla Glass. It has a 3 IPS LCD full HD display of 1080 x 1920 pixels and 401 PPI, with 1500:1 contrast ratio; and you get a 178 degrees viewing angle.
Based on Android Lollipop 5.1.1 with Qualcomm Snapdragon 810 (64 bit with 1.8GHz Octa-core SoC) Processor, the phone runs on OxygenOS with 4G LTE connectivity, an Adreno 430 GPU for its graphics.

The device carries a 4GB LPDDR4 RAM with 64GB eMMC5 storage. This future ready phone comes with long lasting 3,300 mAh Li-Po battery, slots for Dual Nano SIMs, USB Type-C port, Fingerprint sensor and 3-way physical alert toggle switch.

There is a best-in class primary camera of 13MP with f/2.0 Aperture of 1.3 µm Pixels, accompanied by 6-lenses, Dual LED Flash, and an advanced Laser Autofocus feature with Optical Image Stabilisation (OIS). The front facing camera is of 5MP.

Price: Rs.19,999.00

2. HTC One X9
Powered by octa-core MediaTek Helio X10 processor, the HTC One X9 is a 5.50-inch phone with touchscreen display and a resolution of 1080 pixels by 1920 pixels at a PPI of 401 pixels per inch. The display is protected by a Full HD 1080p Curve edge Gorilla Glass.
Running on Android OS, v6.0 (Marshmallow) with 3GB of RAM, the phone is packed with a 32GB of internal storage which can be expanded up to 2000GB through a microSD card.

The HTC One X9 comes with a 13-megapixel primary camera and a 5-megapixel front shooter for selfies on its rear. The cameras are equipped with features like dual tone LED flash, Optical Image Stabilisation (OIS), Pro mode with manual control and RAW format, HDR mode, Full HD 1080p video recording Live make-up, Auto selfie, Voice Selfie, Selfie timer up to 10 seconds and more.
This Dual SIM phone has Nano slots for both the SIMs with 3G UMTS, 4G LTE
Battery Capacity of this phone is 3000 mAh

Price: Rs.20,698.00

3. Moto Z Play with Style Mod

Running on Android 6.0.1 Marshmallow, this phone is powered by a 2 GHz Octa-Core Qualcomm Snapdragon 625 processor with a 650 MHz Adreno 506 GPU for its graphics. The storage includes 3GB of LPDDR3 RAM, with 32GB internal memory that can be expanded up to 2TB.
The device comes with a dual micro-SIM dual-standby (4G+4G), 4G VoLTE.
It is a phone with a 5.5-inch super AMOLED 1080p full HD Display with 403 ppi. Other features include finger print reader and water repellent nano-coating.
The 3510 mAh battery with TurboPower charging runs the phone all day long with 8 hours of power in 15 min of charging.
For photo and video shoots, it carries a 16 MP dual autofocus camera that has features like laser focus and PDAF, color balancing dual LED flash, 4K video recording (30 fps). For selfies it comes with the standard 5 MP front camera along with display flash.

The best feature of this phone is that you can transform it magnetically by clicking on the Moto Mods onto your phone. You can convert it into a movie projector, a battery powerhouse, boombox, and more. But you need to purchase the Mods separately.

Price: Rs.24,999.00

4.Lenovo Vibe Shot

The Lenovo Vibe Shot runs on Android OS, v5.0.2 (Lollipop) based on a Qualcomm MSM8939 Snapdragon 615 Chipset and an Octa-core (4x1.7 GHz Cortex-A53 & 4x1.0 GHz Cortex-A53)
processor. For graphics it has inserted a Adreno 4051.7GHz 64-bit octa core processor.The storage includes a 32GB Memory with an expandable 128GB memory.

The 5.0 inches Display is of IPS LCD capacitive touchscreen with 16M colors and a 69.3% screen-to-body ratio with a Resolution of 1080 x 1920 pixels and Multitouch functionality. All this is protected by a 3.0 Gorilla glass.

The camera has 16MP in the Rear and 8MP in the front. The features in them are Manual shutter button, Pro and auto shooting modes, Optical Image stabilization and a Low light sensor.

Price: Rs.18,399.00

5. Sony Xperia M4 Aqua Dual

This smartphone model from Sony runs with Android v5 Lollipop operating system powered by a 1.5GHz+1GHz 64-bit Qualcomm Snapdragon 615 octa core processor. For graphics it has an Adreno 405 GPU,
The storage of the device has in it a 2GB RAM, with 16GB internal memory which can be expanded up to 128GB.
The phone has the standard 5-inch HD capacitive touchscreen display with 1280 x 720 pixels of resolution.

This is a dual SIM (GSM+GSM) phone carrrying a 2400mAH lithium-ion battery that gives a talk-time of 13 hours 17 minutes along with a standby time of 493 hours.
For photography the phone is packed with a 13MP primary camera and 5MP front facing camera with features like auto focus, image stabiliser and more.

Price: Rs.21,738.00

For the choice of an Operating system, even I would go with the other experts and suggest you to stay with Android for a number of reasons.

1. Ease of use.
2. Easy upgrade
3. You will have more number of phone models to choose from.
4. Available at both low to high prices.
5. More number of apps available for it.