Just upgraded to latest stable plugin (0.4.735) on 10.0.2, but it is unbearably slow.
Simply typing text (repeatedly) into a comment pegs the cpu at 100% and the editor cannot keep up with my typing (and I'm not that fast :-). Pressing enter in a scala file takes up to 1s to be executed.
I've tried disabling scala aware type highlighting, setting highlighting to none, but this didn't seem to make a difference.
Update: Setting highlighting to none and restarting seems to solve the problem.