Out of curiosity I wanted to see which combo is better on final image, great lens on lower Mp or an average one at higher Mp?
So I tested two excellent primes on "lower MP cameras" (90/4 Macro-Elmar on the 18 Mp Leica M9 and 90/2.8 TS-E on the 21 Mp Canon 5D2) against a so-so zoom, albeit in its central position and stopped down a couple of stops, on the king of Mp realm (AFS 28-300/3.5-5.6 ED VR on the Nikon D800).
As you can see lenses matter more than cameras :)