I really wanted to like it, and found it's configuration, package installations, etc. all very smoothly integrated compared to other distros I've run in the past (SuSE, OpenSuSE, Red Hat (pre-Fedora), Mandrake/Mandriva.) Unfortunately it's the most unstable excuse for an OS I've ever run. I don't think I managed to run for an hour before it would suddenly lock the mouse out and freeze the entire system, both with the default vga driver and with the NVidia GLX driver.
So I won't be recommending Ubuntu to anyone in the near future. "Mostly" working and slick isn't compensated for by lockups when I'm used to being able to run linux boxen for weeks or months, never mind hours.