Since the Xbox 360 was released two days ago, there have been numerous reported incidents all over the internet. The primary complaint is that the system is unstable, with games crashing at random, along with the entire system. I can vouch for this, because I have had this happen during NFS: Most Wanted and Project Gotham Racing 3 game play. Some have had far worse crashes than me, however. Some screen shots floating around show many artifacts on the screen after a crash, which forces you to manually shut off the system.
Other complaints are related to heat dissipation and noise level, both of which I can verify again… are very noticeable. I highly doubt that the reported crashes are due to overheating, but rather system instabilities or bad code in the games. The problem seems to be most prevalent with PGR3, so it’s possible that there was a bad pressing, although I have had very little issues with my copy.
There is a lot to read on these problems though. You can check out the quick posting over at News.com, and see some user feedback. X-Box Scene has been doing an excellent job keeping up on top of things also. Check out their forums to see what the users are saying. If you are one of the users affected by these problems, speak out! Believe it or not, there are official forums for the 360, so vent and read others opinions there.