I pretty much use this list as a guide as to whether or not the Nikkor 1.4 series justifies it's price difference against the Nikkor 1.8 series in terms of resolving power to get the full 36 megapixels of the D800.
According to that list, the 28mm is indeed worth it's money alone, considering how it does very well when compared to every other lens in the price range.
The only difference I see is "bokeh" and that extra 2/3 of a stop for extra light. The 1.8 series really outshines the 1.4 series when shot wide open. It doesn't suffer as much chromatic abberation and is alot sharper until stopped down to 2.8 and lower.
Also, one of the tricks to shooting with the D800 is nailing that ISO 100. It's rated at 14evs stops of Dynamic Range at ISO 100. I think the only real competitors around the same price range are the 5DMk3 at 12evs, and the BMCC at 13evs.