Don't take this as condescension. I'm cheering for Microsoft on this one. They need a good mobile device in their line-up. But if you're ready to buy a Windows Phone 7 device on day one... why?
There are plenty of reasons to avoid a WP7 unit - it's a first-generation product, it lacks basic features like cut and paste (although that's coming), other mobile operating systems are more advanced - but I think I understand those differences pretty well.
What I'm curious about is why those of you who are getting ready to plunk down some real money for a WP7 unit are excited. Help me relieve some of my own ignorance.
If it were me, I'd guess the integration of Xbox Live could be a big selling point. I'm a little too much of a cross-platform gamer for that to be a tipping point, but for hardcore XBL players, I can see the connection. But I'm putting words in your mouth.