I have been using Code::Blocks on Ubuntu 5.10 for about a week now. Installed the deb package for rc2. Since then have downloaded from the svn repository and done my own builds twice.
I have found no issues wrt running on ubuntu or the deb package itself. There are, of course, bugs in the main program independent of the platform. I'm new here and am not familiar with how to check for bugs that are known vs. those I might find..