My HTC Hero currently running Android 2.1 and I'm thinking of rooting it and sticking on 2.2.
It flies. I've only got free apps but those that I have would be worth paying for, including a metal detector - I mean, on a phone, who'd have thought it!
I have friends and colleagues with iPhones and I'd say about 15 -25% have had serious issues with them Vs Android, nil.
W7Phone I've not used, not seen (apart from in media) and know nobody with one.
But that's just me