Hi GeronL,
I've been a RedHat family fan since 2001, RHEL and Fedora Core and CentOS, and still prefer it over other distros. However, the company I went to work for (as Sysadmin) this past March is about 90% Ubuntu, which I previously Did. Not. Like... Adaptation time.
I had occasion to put Ubuntu 12.04 LTS on a couple workstations, and the Server version in a VM under Xen on my CentOS workstation. Also built the Server version into a couple of system servers for various purposes.
I agree with you -- it's very stable -- and in addition I find it relatively easy to work with. I'm not a fan of the desktop GUI setup (I'd probably shoehorn GNOME over it given the chance) but it works.
Overall, I second your recommendation of 12.04. Good stuff.
MINT I've only played with a little, it's okay but I didn't really get to know it well enough to form an opinion.
Even if they used GNOME or let me dump the sidebar, it’s still a great Linux distro. If I had some better hardware I would still want Ubuntu, even if I added a Windows partition for playing games.