I know I'm probably going to take flak pretty hard for asking this, both from trolls and from troll-hunters, but this is a genuine and serious question. I need to know. I want to understand what will cause people to part with their cash to acquire WP7 phones (and in particular the forthcoming Nokia WP7 Mango devices). If Mango/Sea Ray is so good that it's worth burying MeeGo/N9 for, I must have missed something.

So...

What makes people want to buy WP7 devices? What are the unique selling points of WP7 (including Mango which people keep telling me is so amazing)?

Please remember that a unique selling point is a feature or ability not delivered by any other OS. Therefore "it syncs with Exchange" or whatever is not a USP.