After a great laptop upgrade, I gave a go on my home desktop.
Issues, none a show stopper, but for the less experienced user, this requires attention.
Firstly, I use Kubuntu, and have been using Wicd for a couple of versions as KDE 4 decided we didn't need static IP's for the longest time.
Networking was completely broken when I rebooted. Wicd was half installed, gnome network manager completely missing in action, and the plasma/kde stuff a mess. Took some CLI antics to bring up the eth0 to get something to work so I could apt-get a solution. Breaking networking is almost worst than breaking X!
Couple that with the known Nvidia issues (again.. How many upgrades is this that have not worked for Nvidia) and it was a mess. The Nvidia issue was really sweet in that once I locked up the system playing, Ctrl-Alt-F2 put me to an out of range indication on my monitor...
All working now, but for an install that was less tweaked than my laptop, I am a little surprised.
One good thing, they finally got rid of that hard drive checking tool that spent six months telling me that HD failure was imminent on a perfectly good Seagate drive. Thanks for that folks, I'm giving gnome another go now.