Everyone I knew who had a windows phone seemed to love it. If MS were taking a run at it today it would likely succeed. The nail in the coffin was Google refusing to write a Youtube app for Windows Phone and THEN blocking the app that MS wrote themselves.
I'm still shocked the EU didn't tear them apart on that move. It's about as anti-competitive as it gets. Honestly I'm still sad they gave up, we could've used a third player, even if they were going to always be a minority player.