It's still getting there. I'd have to say that 10.04 was pretty much the fastest release I've ever used. System speed slowed down in releases after (even with Xubuntu), but 13.04 is somewhat closer to getting back. I tried out the Ubuntu 13.10 Alpha dev release for awhile and was pretty impressed with the speed. That was with Unity running so hoping that Xubuntu 13.10 will be equally speedy.
No announcement yet.
Preview: Ubuntu's Performance Over The Past Two Years