Ubuntu's fine, I just don't like Unity all that much. I think it's clunky and badly put together. If I ever switch to Linux full time (which'll happen when either GIMP gets good, or Adobe ports Photoshop), I'd use either Elementary, or a Gnome 3 distro.
I think Gnome 3 is one of the best desktop UIs I've used. It's definitely different, but once you get used to it, it's one of the most organized and easy to use environments around.