I'm aware that different methods will result in different results. I currently have two needs, 1) billboards....I used to do these on a 11mp camera with no problem as they're being printed at such a low dpi and viewed from so far away, clients do however ask for higher and higher resolution files. 2) artwork for display. the viewing distance on these pieces is often quite close and almost always coming out of my ipf8300. I've just done a 82" piece from the 5dII which produces very nice results, but nowhere near as lovely as the new nikon samples I've seen at similar size - at the same iso under the same circumstances. Pixelation and grain start to creep in at those sizes, standing 12 feet away one won't notice, but this is for display in an office lobby where viewers have the opportunity to walk right up to it and the "regular" viewing distance appears to be about 4 feet.
I'm fairly sold on the 5d3 just for the updated focus system, but wondering if I'll really get a much better image, specifically for enlarging, than the II.