It's quite bug free actually.
It's run by Berkley's boinc system which is VERY stable.
I'm running it at the moment, but you guys should also look into LHC@Home (at
http://lhcathome.cern.ch ) because it's actually useful to scientists rather than being a shot in the dark like Einstein@home.
LHC@Home uses massive distributed computing power to calculate the exact tolerances of the magnets being installed at CERN2 in Switzerland. Unfortunately, since it's directly related to a real-life project, there's a lot of down time, but both run off BOINC so you can run them at the same time and when LHC has no work to give out, Einstein will run at full power.
If you have ABSOLUTELY no idea what I'm talking about, just google "boinc" You'll find it in the first link. Basically it's using you computer's spare power (it doesn't slow down the machine at all) to do things that could be extremely helpful to scientists.
Another one for those environment junkies out there is Climateprediction.net. I beta-tested it, and it's a really legit climate modeling program. Being into physics myself, I've gravitated toward the particle accelerators and graviton detecting programs.
Finally, if you need a cash incentive, check out mersenne.org for the prime95 program. On a 2.0GHz machine, you can have a chance to win 50,000 USD once a month. The chances are actually much better than the lottery, though still pretty far-fetched.
Have fun computing though. These programs are legitimate scientific progjects (as opposed to the search for extraterestrial intelligence which is slightly far-fetched) so you can be a small part of scientific research by joining up!
