Canon designed and built sensor...
wow!
I was going to type this before you mentioned the sensor source and regardless....
It maybe that they are jpeg, but do the files lack meat to them? I think it maybe the bright sky scenes, but even with the gown in the darkness, For some reason I think compared to what I have seen, they lack a little meat, or "refinement" I want to say..? The 1Ds renders images quite different I have to guess. File is along the lines of the 5Dm2. When you start tearing into those files, they start breaking up faster than a 1ds or Phase file.
Knowing this I kept the 5Dm2 for anything but studio work, as I think it is fantastic for such work.
I know, its just my off the cuff impression, but I think it is worth sharing as a first impression. (I know I'll likely hear it :-)