and in the config file I just have shadow settings and such: http://pastie.org/7755376
There is a slight delay when dragging windows do to the vsync method (the movement is very smooth, its just that its slightly delayed behind the cursor), but perfmance in general is great. I can have a shit ton of windows open no problem, the desktop is just as snappy as it was with no compositing, and scrolling in firefox feels far smoother. And I'd assume since you are using a tiling wm you don't do a lot of dragging windows around anyway
Depending on your card/driver you may want to tweak the commandline, you can find documentation here:
Compton is definitely the best compositor I've found for lightweight DE's and window manager, I love that it doesn't interfere with the native window manager at all, so it can be used easily with any window manager and it does nothing more than add compositing and shadows Its recently gotten a new main developer and is under more active development than in the past. Recent versions have been *very* stable for me. The developer is great and responds to bug reports quickly.