+1
Jack hit the nail on the head. I have both the D800E and a MFD kit and fully support Jack's conclusion (and his "howeverbut").
Regarding processing required to achieve the desired result, as you know, Nikon's color rendition is different (not better or worse) than that of Phase One. My processing time with either is more often spent on getting the color "right", than on resolution, micro-contrast, dynamic range or other variables.
I've not owned a D3x, so I can't comment on that part of your question.
Joe
In virtually all areas Jack discussed, I would also agree with his assesments as well as those of Joe and Guy based on my experiece of working with D800/e files, 645D (40mp) files and a large array of test shots with the Leica S2 when I had access to using one for the better part of a few days on two occasions.
There were differences in tonality and color, especially with the two CD based sensors and the level of detail often was as much due to the lens being used as anything else. I would have liked to equalize things a bit and had a plan to test some of the better Pentax 645 lens glass on the D800/e, but that had to wait, save for a few tests shots I did comparing the two with a single MF lens. Interestinly, the D800/e did superbly with it!
When it came down to large prints after optimal post process adjustment of files from each camera, differences were far less noticable than with sceeen viewing of the same files. Sometimes I would notice things that were slightly biased towards the MFD, but again, differences might have simply been due to optical performance of lenses being used as much as anything else.
The one area which did make a significant differences in working with each system was the need for careful selection of good glass and the additional demands the D800/e made on this glass, even more so than the 645D and S2 (although it's hard to make a statement regarding the S2 and its lenses, since they at present, the S2 lenses clearly are some of the best, performance wise). Anything less than optimal optics and the D800e easily and clearly showed weaknesses especially on sides and corners and sometimes in overall resolution. The larger photosites/sensor used with the 645D and S2 seemed to give it some latitude whereby on the 645D, even older reasonably and bargin priced legacy lenses that were considered good but not outstanding performaing optics (in general), did quite well on the 645D across the frame. I feel some of the presently available optics now used with the D800/e may be more of a limiting factor than anything else and once newly designed higher performing lenses are available for the Nikon system, we'll see more of the true potential of the D800/e and possibly differences between the 40mp MFD cameras and the D800/e.
Dave (D&A)