Not saying the 5DII is no longer good, even my original 1Ds still produce very nice file today albeit so many years ago.
I preferred the 5DIII over last generation because its autofocus is hugely improved that in the past I would avoid using markII in studio becuase of dimmer light and less contrast while today I will happily pick up 5DIII for studio use.
What I do find is that because 5DIII has newer and higher capacity focusing engine, often result a higher degree of sharpness in overall picture - true, if a subject is in absolute focus - it is basically the same but critical focus is usually base on how critical we are, especially in field work and with successive sequence shoot, the 5DIII actual made me think my same old lens beomes sharper. The new CR2 file seemed to be richer as it appeared on C1Pro, although with critical side by side test against 5DII (OK, I have to say I am a bit less interest to do camera test, I found go ahead using them for jobs to be more fun) I would give the 5DIII file slight edge over 5DII.
Pingang