At first I was really impressed with the Metro-style home screen. But as I watched this video, actually, for the first time, having now seen Metro several times, I realized that there was something about it I didn't like: I think it came down to the constant movement on the home screen. It actually reminds me of web banner ads. Now I'm sure that's configurable but I think I understand why that wouldn't be desirable. Of course that said I'm sure that's the kind of thing some people will love.
Live tiles are great; on my Windows Phone 7 I can get a lot of context just by looking at few tiles in the "root" display (time, the next meeting I'm in -- hopefully not many -- email count, etc.)
I used an iPhone for a couple of years, and would hate to go back.
I was surprised how static and dull the iPad looked; just a bunch of dead icons that don't do anything for you. Reminded me a lot of the desktop in Windows 3.1
The other thing to realize is that you don't stay on the home screen for long. You see if there are any inrestesting notifications and then move on to what you want to do.
