Paresh,
It's a typical question to answer because some may feel that they can earn better by running a personal blog and the others may not be able to afford it. I don't like calling it a personal blog when it is serving advertisements. So, let it be just a blog. However, from a blogger perspective, it is always a good idea to have own blog. Not only, the freedom to write topics of our own choice but also one can have a complete control over his actions and content. But there is a downside.
It's not that easy for everyone to maintain a blog and take it to the top level in SERPs. Only a well trained and knowledgeable SEO expert can do it. Or at least he needs more experience may be an year, two or even more. So, in that case it's better to hire some experts or just write for revenue sharing websites and earn from them.
Both has their own advantages and disadvantages so, a clever step into the future is all it takes. What do you say?