This is my 2 cents;

As a consumer I have been using Windows Phone 7 back since I reviewed it in November and I must say I love the operating system. It is fast and ridiculously responsive. I have turned on my N900 from time to time and it is painstaking how slow it is. As for 'features' it's not really missing much except USB OTG. The app market though is very healthy, the current fastest growing out of the major three.

From a Developer perspective there are other bonuses too; the platform is ridiculously easy to develop for and the tools are world class. Microsoft are renowned in the business for making their developer tools outstanding and the ones for Windows Phone 7 are no exception. I personally love developing for the platform.

From a world wide approach it makes sense. From a competitive advantage point of view the Maemo / MeeGo customers couldn't competitively sustain a company like Nokia and they needed to change.