Some of the major differences in Ubuntu and android can be listed as below.
1. Lock Screen: Android uses a lock screen wherein you can lock things up by means of a pattern, or password. Ubuntu on the other hand won't give you any lock options. They call it "Welcome Screen" that can be opened by swiping .
2. Navigation: Android uses buttons for navigating through apps, to access recent application or close an application. As a general practice, there are 3 buttons-Home, Back and Menu. Ubuntu has NO buttons! All sort of navigation is done by gestures. SWIPE is the Word. Swiping from right opens the list of recent apps, swiping from up brings up notifications. A swipe from left opens up favorite applications and a swipe from down will open menu in specific applications.
3. Task switching: Ubuntu presents somewhat complicated way of switching between tasks. You just swipe from right to access the recent apps, and from this list you can access the app you need. But, you need to open the application. Android opens task switcher on long pressing home button.
Ubuntu is still at nascent stage. It would not be possible to compare it to Android. For the time being Android is the KING.