Why I left Ubuntu
I was a great fan of Ubuntu and Canonical. I loved the pre-Unity versions of Ubuntu. I found the last Gnome 2 version to be especially functional and polished.
When Canonical switched to Unity on 11.04, I tried it and mostly liked it. Admittedly, there were some issues but I really liked the fact that Unity did a better job of maximizing the screen real-estate available to applications than any other desktop environment I have used previously. I was hopeful that the wrinkles in Unity would be worked out in the next version and was just about ready to pay for support from Canonical for all the systems in my home, mostly as a thank you, when Ubuntu 11.10 came out.
Ubuntu 11.10 seemed to be a lot buggier overall. Unity would do weird things to my applications and sometimes make the desktop unusable, forcing me to drop down to the shell to restart X. Pulse audio on this version was a dog and would simply not work with a sound card I’d been using successfully on Linux for about 5 years. I also discovered a number of newly introduced library compatibility issues that broke some of the commercial software I needed for my job.