I loved my iPhone 4, but I'm not missing a single app since shifting to Android. I bought the Xperia S as a stopgap with the intention to get the iPhone 5 when it came out, but decided to keep it because going back to iOS would feel like I'm losing features, plus I always felt like I was tethered to my laptop. I hate the term "walled garden" with respect to iOS, because it had some advantages, but in day to day use there was always the feeling of 'what Apple says goes'. No default app selection was a huge one - it's on OSX, why not iOS?
The built in Xperia "Swype" style keyboard is faster to use than the iPhone's, the text correction/prediction is far better (it gives you 3 or 4 options not just one - that tiny 'x' to dismiss the suggestion on iPhone never worked for me) and just being allowed to set a default browser and YouTube app is a huge improvement. I can go to Google Play from any machine and install apps directly to my phone/tablet. Notifications are better.The camera has a great panorama mode, too. Battery is fine compared to my iPhone 4. Earlier Android releases were janky, for sure, but IMO it has caught up and iOS is being left behind. And I think Infinity Blade was massively overrated. More a showcase of "look at these graphics on a tablet!" than anything else.