Other than the fact that Apple is the evil empire and Jobs is Emperor Palpataine, why wouldn't you go back? I ask because I have been considering the reverse, that maybe it is time to join the dark side.
Honestly, I have been tempted at times since I got my TBolt. In fact, my wife has a Fascinate and has gotten to really hate Android. To her, it is non-intuitive and kludgy. It certainly has not been as reliable as her Iphone was. Then again, she is not a techie and has little patience for learning curves, so the fact that Apple packages everything up for you in a nice little box is appealing.
I, on the other hand, have spent almost 40 years in IT and new tech doesn't scare me. I'm getting to an age where I don't like a lot of learning curve either, but I can adjust. There are a number of reasons I don't want to go back into the IOS world. Some people will understand and some I could get flamed over (may not go into those as they are moral/religious issues).
1. The closed nature of IOS. If the innovation does not come from Apple, they don't want it.
2. Jobs has way too much say in what apps are available. Flash is the most visible of them, but there are other decisions he has made and apps he has banned that have told me that if you don't agree with his world view and you submit an app that he disagrees with on a philosophical level, it will get banned. The same is true if your app happens to offend some special group of people, it will be banned. I believe in the open exchange of ideas, even if I happen to disagree with them. To me, the only apps that should be banned are those that contain malicious code or help people break laws.
3. The Iphone screen is just way too small. I need the extra real estate my Tbolt gives due to some eye issues.
4. I HATE Itunes with a passion. It is way too restrictive. Did I say I HATE Itunes?
Those are the primary reasons I don't want to go back. Others may well have additional reasons (rooting, etc), but these are mine.