I've been doing this on and off for a while now, and I'm at 430... But the impressive part is that my average is still at 17 hours per unit, which means I've donated a BUNCH of time to them...
But I'm REALLY considering dumping SETI in favor of another project. Recently my machine just sits there and does nothing while SETI can't connect to the servers... It's been about 18 hours now and I still haven't been able to get a work unit!