I tried Ubuntu for devices — once I figured out what I was doing wrong (you have to flash your device to complete stock and wipe it beforehand), the install went pretty well.
The system is beautiful. The way to navigate through the UI is beautiful as well. You swipe from the right to switch between apps. You swipe up from the bottom very lightly to access the app’s context menu. You swipe from the top to access your notification panel, and you swipe from the left to access a quick launch menu of apps.
However… there aren’t many apps to speak of yet, and the ones that are there are mostly web frames.