I've gone back-and-forth; since I bought my first iPhone in 2007 I've had every iPhone model (the 5 will be the first I've not owned) and on the Android side I've had the EVO, the EVO Shift, the Nexus S, the Galaxy Nexus, a Skyrocket, and the Nexus 4 which I recently sold and went back to using my iPhone 4 full-time (I sold my 4S over a year ago).
Good grief that's a lot of phones when you type it all out.
Anyway, as much as I like Android and the flexibility it gives you, there are drawbacks that keep pushing me back to iOS. For example, stock AOSP ROMs are in my opinion generally cleaner, better-looking, and smoother than the skin jobs that you get from non-Nexus OEMs like Samsung. The problem is that the stock Android OS is missing a lot of features and common sense stuff that a lot of ROM developers include in their ROMs, so you're tempted to flash. These ROMs invariably have other bugs or missing features (Google Wallet not working, for example) or are laggy or the developer dicked around with the color profiles and made the colors "more realistic" whatever the hell that means. That ROM also came with a customized kernel that's draining battery faster so you start looking for a better kernel but to really manage that kernel you have to buy an app and oh this version was undervolted too much so it's causing the phone to crash so you have to go into the bootloader and flash your last nandroid to get it back and find an updated kernel that's battery efficient and stable. By the way the sound profile in stock Android on the Nexus 4 is too damn quiet so now it's off to find a mod that will boost the audio because you can barely hear DAG doing his Teddy Pendergrass schtick on Adam Carolla even with the volume turned up full blast so you have flash a zip file in CWM but Google released an update that broke the volume boost feature so...
At first it's fun customizing your phone like that but, as I've gotten older and less interested in tinkering with my phone and just want to use it for stuff I've come to the conclusion that the iPhone is a polished, fully-functional device that I am happy to use without dicking around with it right out of the box; an experience I never had with an Android device, even the Nexus devices which frankly are like beta devices for Google to play around with on my dime. With my iPhone I don't worry about whether an app is going to hang around in the background with a rogue process sapping my battery (a constant issue in Android and the old Facebook app, for example, which drained 50% of my battery in two hours one day with the phone sitting on my desk untouched). I don't worry about whether this ROM/Kernel combination is going to give me the best battery life or best features or best looks. I don't worry over whether or not an app is optimized for my handset/OS version despite the myriad others out there.
I don't worry with iOS. Plain and simple. And that's the point I'm at today.