I tried various "weird phones" on my way to standard Android, among them a high-end WinCE phone (Xperia X1a) and a WP8 one (Lumia 520). Make no mistake about it, WP8 was a good mobile OS, even if they did stick the dreaded "Windows" name in there. Smooth, reliable, battery efficient, well-thought-out UI. But alas, too late. By then Android had captured the "not iOS" market and it would have taken a miracle to bring a third OS to the mainstream.

I very briefly tried WP10, and it actually seemed a step backwards; in their desperate attempt to somehow unify the desktop and phone thing, be it in code base or user experience or whatever, they tried too hard.