It just depends, small developers have more of a chance on android in my opinion because less competition also there are plenty of success stories on ios but there are so many failure that cost developers a ton of money. Plus more users. Most success stories come from huge big name developers. Gamevil, Com2us, Chilling, etc but what you dont see many of these companies start out with failures too. I think Rovio had made like 13 games before Angry Birds. If you're just starting android is the place to be if you're willing to work and not give up because you can constantly update your game without waiting on approval and get instant feedback to make your game better.
Many big companies think you're just suppose to make a game and let it sell because hey we didn't make any mistakes. Wrong. Every single EA game had problems on android as in not working, crashing, or not downloading additional data correctly from the start but did they work hard to fix it? No. Even with these problems and many low reviews due to huge problems. Most of there games still got more than 50,000 download that's a lot for a game with no updates, broken, and no support plus bad reviews. I can imagine if they actually tried. I think they just expected people to just except problems like many ios users or not have to actually support. Plus they just buy and can't get a refund when something wrong. Many developers want Apple to handle all the problems and not give people refunds etc. Well that's good for the developer but what about the user.
Also, while your game may get promoted nicely the first week on ios which you don't have control of actual release date if it goes off the radar like most games after the first week then your game is pretty much lost forever unless its really good or you have a big name. Plus what if you made a critical mistake upon release and low reviews made sales bad and the game lose popularity while you're waiting for Apple to approve that fix. And that fix probably could of kept the game selling well but most people would never know the game is fixed because now your game is off the radar and there is no just in section to show people your game again after an update. Where do you think the 99c sales came from? Even big companies have to do this just to be seen again even with good games. While on android if you make it to the top you stay there for a long time especially if you keep supporting the game.
So you might make a lot of sells initially but the life of your game dies faster than you could ever believe. If you're a big company coming to android expect to support your game or get lower than expected sales bottomline. So hire a tech or two to support android.