Earlier quoted context omitted.
What UI? The UI of the 65,000 full screen iPad specific apps, or the UI of the 16 Android Tablet apps? Have you actually tried a Xoom?
Yes, I've tried a Xoom today, I also have bought an iPad a while back. Have you tried a Xoom yourself? I don't really see the relevance of the number of applications to the the UI experience.
The relevance is that the apps are what provide the UI.
For the iPad there are 65,000 of them customized to utilize the full screen. For the Xoom, there are 16 customized for the full screen, and the rest are literally just blown up phone apps, many of which don't even rescale properly.