DxOMark has posted their analysis of the 5D Mark II. If you look at the comparison to the 1Ds Mark III, the 5D2 is nearly identical at ISO 100, with very small numerical advantages in some areas going to the 1Ds3. As the ISO increases, the 5D2 pulls ahead a bit in nearly every test. Go see the results for yourself. Lab testing is only one part of the story when reviewing a camera, but I think these results clearly indicate that the 5D2 can go toe-to-toe with the 1Ds3 in terms of raw image quality…that is, once those pesky black spots go away.