Actually Windows Phone 7 inside *is the good old WinCE*. But Microsoft in its evilness does not allow small developers to run their wince apps in WP7, they only allow us to develop crappy .net applications, but Microsoft and it's top preferred partners do develop native apps for it.
In WP8 I heard that they stopped using the wince kernel and are now using the normal windows kernel, but still 3rd party developers are limited to the crappy .net
That's why I prefer the iPhone and Android. They allow us to develop native applications in Pascal. And that's why I will never buy a Windows Phone device.