I have never used Windows Phone ever, but I developed for Windows Mobile once and I had to cry a little. The complete inability of the designers to understand a phone is NOT the equivalent of a desktop pc (having to use the stylus to operate a telephone is just not practical, nor has the start menu principle has any benefits, and especially not on a phone) plus it being much more unstable than even the lousiest Win9x incarnation... It's just... gah!