Overall, Ubuntu Touch does work well on the Nexus 7. The only tweaks I had to do was to remove the file /home/phablet/.display-mir to avoid the "flickering-of-death" issue occurring when displaying the left toolbar.
It's a bit slow, but usable. Everything seems to work beside the camera that is not supported for now.
I was able to browse, add online accounts like Facebook and Twitter, listen to music and watch some online videos. Movies on the local storage were not playing at all. I did try some MP4 and some Ogg video files, but they never played, only showing a black screen and no sound.
Beside that, the experience was quite good. Some freezing occurred from time to time but nothing dramatic for a version of an OS that is still in preview on the Nexus 7.
I cannot say that it can be used as a main operating system for now. There are still too many missing apps and features. But if you like tinkering with the latest and greatest, go ahead.
I reverted to Android as I still need to use that device for other purpose. I will keep an eye on the developpement of a Ubuntu Touch as the next round will surely be more stable and more usefulness.
Great job Ubuntu Team!