I have to admit, I like the UI on the Windows 8 phones. While Windows 8 doesn't exactly translate well on the desktop... it works fine on the phone as far as I could see. It's at least drawn nicely and has a different design than iOS and Android.
Unfortunately there are just too few apps available. I went to their app store and only a small handful of my apps had a presence there... and Google's stuff was all third-party wrappers to offer some Google stuff. Honestly, that was enough to turn me off.
I guess it's circular... people won't want it if the app selection stinks, but the devs won't make apps because it's not popular.
Note: I got an Android instead.