From everything I've seen and heard, the Android phone is comparable to Linux, ie more flexible and powerful but it can get complicated to use so it's a power user phone, while the iPhone is like a Mac, it just works, even your grandmother can learn to operate it. The Windows phone looks like a toy, but it's market share is so small that it really doesn't matter.
I haven't really compared Android vs iPhone ease of use (both are pretty user friendly), but so far all Android phones I've seen were bought basically because it's cheaper (free with the plan), not based on technical merit in any way. It's basically what you get if you don't want to spend the money to get the iPhone. It's not the user interface that's the main differentiator for me either, and I don't see how some people here think it attracts different age groups or whatever based on that. It mainly needs to be non-horrible unlike the WP8 phone which I can't see anybody buying but the most extreme MS fanboys (and possibly only the blind ones... I mean, no-contrast white on yellow?) Most people would be perfectly happy with the other two.
I've seen some users who had issues with Android phones (performance, spam, malware, etc) that I haven't seen iPhone users experience. Meanwhile, I know that the iPhone has a pretty good program to sync music (with smart playlists and all -- using the same software as our ipods) which is a very
big deal for me, it has by far a better app selection (that's where the money is, so that's where the devs go, and the iDevice devs typically value things like user experience more) which is also very important to me (Apple's store is better too), and if you buy an app for your iPhone then it'll also work on your iPod and iPad (everything just works between your devices). I also know for a fact that it works great in an enterprise setup: you can very easily check your emails from exchange server (we replaced our BlackBerries by iPhones). It also has a lot of "premium" features, like Siri and FaceTime, a far better LCD display, arguably a somewhat better OS, the battery life is better than most Android devices, the on screen keyboard typically works better, etc. An iPhone gets iOS updates (if you have a 4S, you're getting iOS 6 now), unlike if I bought some Android 2.x device from my phone company in which case it'll run Android 2.x forever. The hardware is awesome but yes, it's expensive for sure. I just view it as a very good but premium phone (which pretty much just works). If I wanted a great smartphone and that I had the budget, that's what I'd get. And if I basically wanted that and didn't have the money then I'd get an Android phone. As simple as that.
Just my $0.02 (we're pretty off-topic, BTW)