Since my post above on Jan 18, I made two changes...replaced the D800 with D800E, and, prior to taking delivery of the D800E, had Nikon go over it and my 500mm f/4 VR separately and tuned together.
Initial results are barely off the presses. Had just a few hours each day last weekend to try some photography around feeders here at home. As Steve noted, the detail has the potential to be incredible, especially when shooting tight near the minimum focus distance.
I plan to stick with the D800E at least until next winter and will see what I learn from now till then. My initial impressions with songbirds are favorable. I will note that if feather detail is achieved, moire is frequently there if viewed at 1:1 in Lightroom. Looking forward to seeing a range of applications throughout 2013.