The biggest difference between these cameras is going to be in the color and depth. Recently I had a friend in the studio with a D800E and we compared his files to mine. The D800e picked up lots of detail and I was impressed by it, however the differences in color were pretty large. Areas of skin and fabric that had lots of subtle color changes came out flat in the D800E files. It was weird. You could see the little hairs, strands of fabric, so the detail was there, but the color at 100% was all mushed together. I'd think that the H3D22 would produce a more pleasing and real looking image at least at base ISO than the nikon. But how much difference makes its way to the print is hard to say.
Did you do a side by side test?
I did some comparisons between the D800 and the Phase One P25+.
I found that results were very close color wise at base iso. However quite different exposure
was required. Less with the Nikon and more with the Phase back.
What I did find is that with fine textures any moire correction on the P25+ resulted in mushy
color. Even mild correction required on natural textures like wood grain would mush up the
Now that said the D800 is not immune to moire, but it is much less likely to rear it's head
and if present it is far easier to correct.
As far as skin tones go the D800 and P25+ each have their respective advantages.
I find high key lighting of skin tones far better on the D800, same goes for skin with shine, especially
on black skin.
On the other hand I do like the slightly less real pastelly touch that I got with the P25+ on
skin tones with with reddisnesses to them. However with a few steps in photoshop I can
get the same thing with the D800. Keep in mind I'm talking about subtle differences.
As far as skin tone with black and white conversions the difference is much bigger.
D800 wins hands down. Both highlight and shadows of the blue channel are just way cleaner.
About the same difference that I found between the 5D III and D800.
Also anything other than base ISO on the P25+ would not hold up against the D800.