I've always been an iOS kind of guy. I've got the iPhone 4S right now and plan on getting the most recent iPhone available when I can upgrade again next year. My friends have Android phones, and I just can't seem to like the OS. A lot of people like it, but I'm not one of them.
iOS just feels cleaner and smoother to me. Also, once you throw a jailbreak on it, there's not a whole lot you can't do. iOS without a jailbreak is no good for me, but with a jb, it's everything I need. Different themes, tweaks, and fixes make the OS so much better. The sad part about jailbreaking is that hardly anyone uses a jailbreak for more than piracy, which isn't what it's made for at all.
I would like to try an Android phone sometime, but it seems like a hassle to get used to a new OS when I'm so comfortable with iOS. It'd be like switching from PC to Mac, more trouble than what it's worth. Unless there's something an Android phone can do that my iPhone can't that blows me away, I don't plan on switching.
Sort of OT, but one thing Apple needs to fix is the screen size. The 4" screen on the iPhone 5 is still too small. I think somewhere around 5" is big good, but bigger than that is where it starts to become a negative for me. I hate the phone's that have ridiculously huge screens (Like 5.8" and above). My pockets are full enough between my phone, wallet, and keys, (and occasionally DS). I don't need a gargantuan phone filling my pocket.