It is true that at high ISO 6400 and above the images converted in ACR are not as good as the images converted in DPP. It seems that some Nikon users become upset that the Canon 50D isn't perfect. Oh well do they think someone will sell all their glass every time a different camera company comes out with a new model that may be better. And it's up to Adobe to make it's ACR work properly not Canon. I went from the 20D to the 40D and now the 50D. The 50D has 50% more pixels a better LCD HDMI output and a better live view system. There are several reasons I like it over the 40D.
And if your a Nikon user that has a problem with it. Get a life!!!!!!!!!!