This seems to be a pretty big debate with the iPhone and LTE phones coming out on Verizon.
I can tell you why I am switching to the iPhone when it's released. All of what I say is based on personal opinion and experience.
I've owned three different Android phones: HTC Droid Eris, Motorola Droid, and Motorola Droid X. I've had "issues" with all three at some point.
Eris: Extremely SLOW. I liked HTC's solid design, but hated the slow processor. Also, Android 2.2 never came while I owned the phone, and I felt like I was held back because of it.
Droid: Really liked the phone, but it was a little bulky and I found myself annoyed with the slide-out keyboard. After the Froyo update, the phone went crazy and my speaker would randomly mute. I missed a lot of calls due to this and performed MANY battery pulls.
Droid X: Fantastic phone. I'm not too bothered by the size, so a 4.3" screen isn't an issue. Hardware is very solid and it is extremely fast. Recently, an application I downloaded (still haven't figured out which one!) has been causing my speaker to become muffled and the volume is much lower. Once again, I am missing phone calls.
Don't get me wrong... I don't mean to bash the Android OS. I just find myself downloading a lot of applications that end up being a disappointment, and the little bugs I've dealt with have been enough to drive me nuts. I feel that Android is more for someone who likes to "hack" their phone to tweak it to their unique needs. The OS has a lot of ways for someone to customize it, but I just can't get into it. Plus, the media player is really disappointing.
iPhone: Now that the iPhone is finally coming to Verizon, I'm definitely going to purchase one. I've been a Mac user my entire life and feel that the iPhone is the missing puzzle piece. Knowing that a company manages its hardware, software, and OS makes me feel more comfortable buying into its technology. Yeah, it may not support LTE or simultaneous voice and data, but those things aren't as important as the winning combination of reliable hardware and software.
By the way, I'm not an ignorant computer user--I work in the information technology field, and mainly with PCs. I own both operating systems, and find myself doing more programming work on the PC, and just about everything else on the Mac. Everyone asks me why I've never dual-booted my Intel Mac to run Windows--I just like my Mac the way it is! Plus, who doesn't want to keep work and personal life separate?
I like things to just WORK. Apple may not be the first to adopt the most cutting-edge technology all the time, but they somehow find the most important things and put them together into a sexy, user-intuitive device that can fit many people's needs.
Phone contracts are long-term commitments, so I hope all of you out there who are debating between the two OSs make the right decision for YOU. I've been doing my research for the past three years and know what's best for me!