Windows Mobile is Windows CE, though not everyone liked it. I had a Tmobile Dash (HTC Excalibur) back in the day and it was pretty cool. Finding apps that could run on it was where I had trouble. If you remember, you had to download them as CAB files from your typical web page. WinMo and WinCE apps and games could run half the time. The other half of the time there was some problems with the screen resolution or some library was missing, or something else.
I think the transition to Windows Phone 7 could have been handled better. I never saw one out in the wild, and everyone that developed apps for WinMo stopped supporting the platform when MS abandoned it... and didn't necessarily pick up 7 development. There was zero compatibility, and WinPhone 7 didn't do well enough for people to care about it. When I moved on from the Touch Pro 2 (6.x I think), there was a newly released HTC HD2 phone with a huge screen that was initially popular before joining bargain bin thanks to Microsoft, and I had more trouble finding apps for my old phone as time went on (even some apps I already had at some point were gone).
Microsoft had the resources, background, and talent to do it right, and they knew more about phones than Apple did, yet they failed anyway. The fail was so epic, it's probably worthy of a movie script.