We have all three in my family (not in my house though)...
Everone likes their phone for similar reasons and it seems like they all work well enough. I've refused to upgrade to the new iOS on my phone though since I love the Google maps far more than turn-by-turn directions.
But, turn-by-turn directions was, by far, the best feature of my Android when I had one, even though it was a terrible phone. Rule learned: Don't get a cheap Android phone, get a REALLY good one.
Now, my office has gone to iPhones and I personally use an iPhone, and it just works. People in our office don't complain about them that I know of, and everyone seems to find something new and useful to use it for on a regular basis.
Still, my Dad likes his Windows phone and his network allowed him to turn on local hotspot, so if you are without internet, you can turn that on and get your PC online for needed AH time.
The Android phone I had allowed for tethering, but it still may all be network dependent. My brother just got the Galaxy III, and he's really happy with it. I'm not in love with the larger screen size personally. But, the blessing and curse of Android is the open nature. So, make sure you are buying a quality phone, on a quality carrier, with a quality network. Not one of those things seem to matter with iPhone.
