I can't buy in yet because I'm not "set up" to do so yet (it will be about 2 days until I can actually buy).
My advice, though, is to wait until you see a run-up well past 600, such as a recovery to 640. Right now it might have farther to fall, and I just hate buying anything while it's on a freefall, even in this situation where 600 has seemed to be the right spot to jump in for the last several weeks.
565 as I type this.