Today I upgraded the last of my three main PCs to the beta version of the new Ubuntu, Feisty Fawn (7.04). While it is a beta, they're very close to the full release at this point, so the code should be pretty close to final.
I haven't seen any major issues thus far. My xorg.conf file needed some tweaking on the desktop, but I can hardly fault Ubuntu for having issues with the three monitors that X always needs a ton of finagling to get to work. Samba had a hiccup on my server box, but that's more related to the hacked-up smb.conf file. The laptop installed flawlessly. All in all, a pretty painless upgrade.
Probably the new feature I'm most stoked about is the wireless manager. FINALLY, there's a nice and easy way to browse and connect to available wireless access points. The lack of this in past versions has bitten me a few times and I never was able to find a nice third-party app for such a purpose.
If you're using Edgy and want to give the beta a whirl, you can get the process started by running the following at a command line:
gksu “update-manager -c -d”
And that's it! The upgrade GUI will walk you through the entire process. I can't wait to see where the Ubuntu team takes things from here.