I've had expensive and inexpensive androids, and a couple iphones.
I enjoyed using my android because the variety in apps, customization, and such. But as a gamer, I found the games a tad lacking (when I owned them, that is.)
Plus android phones get bulkier and larger as the price increases which is a huge loss in my opinion.
iPhones... They're consumer magnets, and you have a brand-name tax due to Apple being money-hungry. However, for $99, you get a powerful iPhone more than capable. In fact, more so than the first couple of generations.
The apps come in many, but many are terrible. Plus they get filtered and removed due to Apple's policy of things being PG-13.
Games, oh man.. Games.. Infinity Blade 1-3 are the greatest games I've played on any mobile application. I dislike mobile gaming but they changed my focus a LOT.
Personally, I'd own an iPhone because of Infinity Blade and IB purely. But android is overall better. Much better.