I purchased a 5D MkII last December after upgrading from the original 5D which I owned for about 4 years. Over the past year I've noticed that the MkII seems to regularly overexpose outdoor shots a couple of stops. I primarily shoot in Av mode, sometimes in P. I've even seen this with still subjects where I fire off multiple shots and one shot will be overexposed and the adjacent frame is exposed correctly (no refocus or recomposure between frames). A lot of times I just end up adjusting the exposure down to compensate. I never had this problem with my original 5D as the metering was almost always spot on, so you would think the more advanced MkII would have better metering, not worse. I've seen some other posts around the web on this same issue but never saw a solution. I've also had the occasion of a flash photo just turning out completely black even though the flash fires and then the next shot is ok. I will probably send the camera into Canon next month to have it checked out but figured I would throw up a post here as well. Thanks!