My main work machine is still on Ubuntu 10.10. I had installed 11.04 on my spare laptop, but hated Unity so much I only ever booted into Gnome Classic. I was hoping things might get better with 11.10, but things are now very much worse. To the point where I'm looking around for other distributions. I suspect, like Linus Torvalds, I might start looking at XFCE.
Anyway, after upgrading my laptop to 11.10, I was disturbed to find it wouldn't boot up: you just sit there looking at a message which says "Waiting for network configuration". I'm fairly techy (and have a spare computer), so I was able to find the answer, which was to drop to a shell and move a bunch of files from /var/run to /run. But imagine a non-techy person trying to cope with this. Congratulations Ubuntu, you just lost market share.