I'm typing this while running the Ubuntu 9.10 Karmic Koala beta Live CD (so I can check it out without touching the hard drive--OK, Live CDs will look for swap partitions and use them, so I should technically say "without touching any files on the hard drive".) It's definitely beta; a stray GNOME application or two died for some reason, though it didn't affect my ability to use the system.
It's pretty; the default theme is more orange than brown, and it booted quickly, even though it was having to load from a CD rather than a hard drive.
You'll notice that the countdown has started again; soon it will be officially released. Give it a try.