Compare to 1ds Mark II:
Picture quality is not really noticeable, bigger view finder, different shutter click sound, little bit lighter. Sure its a nicer camera, I like it.
I shoot with Mark 2 and Mark 3. Yes I like mark 3 better, because of bigger viewfinder and it shoots, feels and sounds better in your hands.
I wish it would have not only Small-Raw function, but Medium-Raw as well. That would be nice. And the price would be around 5 or 6 thousand.
But 1ds2 is a great camera still!