Firstly I don't like the way the interface looks. Plus having your phone boot into Windows just makes me shudder.

I think Windows Phone is too much of a 'me too' product to be a proper success. Most people who've had Windows Mobile will avoid it like the plague, I can't see ANY iPhone users wanting to switch, and you get a much better choice with Android.

So ultimately I personally believe it will be a minor player with maybe 10% to 20% market share, which for a company of Microsoft's stature will be seen as a failure.