Yes, I've seen Michael Reichmann's page on this when it went up. His conclusion is broadly correct - the A900 is fine to 800, compared to the others. He is not being honest about the Canon as it has an entirely different image structure to the Nikon, not 'equal'. The 5D MkII retains much more colour information up to 6400, but uses some very strong raw NR and sharpening routines (I don't know exactly how they manage this) which make smooth plain areas better, and at the same time emphasise fine detail.
There are some other interesting claims going round, one of which is that stabilisation systems do not work if the camera is aimed up or down, and that you can see the problems with lens-based systems but not with SSS. A lot of macro shots are taken aiming down.
I'm checking out galleries and posts from all three cameras to view as many pix as possible right now, and one thing is clear - no-one is trying to shoot high ISO with the A900. There are some fantastic image sets around from the A900, like this one:http://forums.dpreview.com/forums/readflat.asp?forum=1037&thread=30478881
Pure low ISO landscape exactly where the camera has its strength. In contrast, Nikon and Canon early users are keen to see whether the cameras match the D3, or better the 1Ds MkIII, or are better than each other. I only singled this shot out because it's only at ISO 100, supposedly the D3X native sensitivity, and no matter whether the sky is dark or the subject difficult, it's not looking as you would expect. I know for certain the Canon would not do this; I don't think the A900 would at ISO 100, but it might at 200 or 400. Even then, I would process the file to eliminate the problem; there is no need to have this amount of noise.
I don't think you would ever have a problem as I doubt you would even bother to photograph something as boring to start with!