I will be thoroughly testing the D800E in DAP, and if I can get the D800 also, I will be doing side-by-side testing as well.
The Nikon D800 and D800E offer breakthrough resolution, leaping into medium format territory with two models: the D800 with an anti-aliasing filter (D800) and the D800E without an anti-aliasing filter. Kudos to Nikon for a ground-breaking choice— the first 35mm DSLR without an anti-aliasing filter!
An anti-aliasing (AA) filter is used to reduce moiré, but has the undesirable side effect of blurring the image, as that is what it is— a blur filter. Read about what happens when an anti-aliasing filter is removed.
Moiré can be a serious problem with some subjects, see Making Sharp Images for an extreme example of moiré with the Leica S2, and how to mitigate it. Mediocre lenses generally do not have moiré issues, and the better the lens the more likely that it will produce moiré (higher resolving power and contrast are key factors).
I hae rarely found moiré to be an issue with my 18MP Leica M9 in over two years of shooting, though the truth is that there do exist undesirable color-speckle artifacts (not moiré) that are also related to that lack of an AA filter. The 36-megapixel Leica S2 can have some pronounced issues as I show in my review, but it’s photosites are also much larger than a 36 X 24mm sensor.
With 36 megapixels on the 36 X 24 Nikon D800E sensor, I expect the issue of moiré to be of little concern for the vast majority of subjects. However, if one regularly shoots artificial (man-made) subjects with regular patterns or tessellations of very fine detail, it could be an issue.
Example with/without AA filter
Shown below is are two images from a Nikon D700, modified by maxmax.com. At left is a standard D700 crop. At right is the same camera without the AA filter. The difference is very significant. Mouse over the image at left to quickly compare.