I've been a Mac user on and off since the mid-80s. My first smart phone was an iPhone 3G, it was awesome. My current phone is a Thunderbolt on Verizon's LTE network. Even though I only got it in March, I'm dying to replace it.
If you like things that "just work", go for the iPhone. It's intuitive, its interface is consistent (not a minor thing), and it just plain works. As I understand it, iOS 5 solved a lot of the issues that caused me to choose Android the last time around.
My Android phone is on the LTE (true 4G) network. It was stupid fast for the first few weeks, 13Mbit/sec or more. Now the network is either crowded or throttled, and it's slower. Also, the LTE radio sucks the juice right out of the battery, you can practically watch it drain. My phone won't go a whole day of light use without a recharge. The interface is completely inconsistent. In some apps, the "back" button does one thing, in others it does something completely different. Even within the same app, buttons do not behave the same way each time.
The one thing that Android had going for it when I signed on was great notification systems - blinking LEDs for emails, email subject lines presented on the lock screen, custom notifications per mailbox, etc. iOS 4 couldn't touch it, and I really, really need to know the instant an email arrives. iOS 5 has supposedly filled in a lot, if not all of those blanks (I still don't think it has a blinking LED).
I'm a computer guy, I thought I'd want to tweak the phone and play around with software, etc. I was wrong. I just want something that works and that has NOT been my experience with Android.
My hearty recommendation? Get the iPhone.