So what is worse on the 5dm3 compared to the 5dm2

From looking at the review, it appears video quality takes a small hit on the 5dm3 compared to the d5m2. I'm sadden to hear that.

What else if anything is worse?

I'm a Nikon guy thinking of jumping ship because of the oil/dust issues with D600 and autofocus of the d800.  The 6d spec wise seems to be weak in some areas so I was now going to look at the 5dm2 and 3.  If I go Canon I didn't know if I should splurge on the 5dm3.

My biggest considerations are dynamic range, low ISO and sharpness. (I'll learn whatever the menu and controls do and get use to ergonomics)    Shooting landscapes mostly.  Like video but I am not going professional with it.

I might pull the trigger around Thanksgiving if some deals start coming out for the holiday season but I know that is probably doubtful.

Bryan