Windows Mobile 6.5 was a little better and enjoyed a very brief period of praise before getting pulverised once again due to Android 2.2 and iPhone iOS4.
So what has changed?? Absolutely everything. Don't make the mistake of thinking Windows Phone 7 is an update of Windows Mobile 6.5. It's a completely new operating system
Windows Phone 7 - The new mobile OS contender - Inspect-a-Gadget