Safari was pretty flawless outside of Facebook for me, but this makes even FB run at 30FPS+ thanks
Now lets hope they can remove the odd jutters that occur with 10.9!
I'm sure they will fix the UI slowness in 10.8 too, it's just a matter of time. If you put the dock on the side of the screen, dock magnification and window minimize animations are 100% smooth, whereas when the dock is on the bottom, you get stuttering. This leads me to think it's something with the dock's frosted glass reflections not being rendered efficiently.