I selected the second option. Sharper is not always better, so that's not an accurate reason. But sharpness when needed is well worth the risk of moire, which is a risk that can be avoided by a knowledgeable photographer, and which technology causes to become smaller and smaller even in the cases when due to photographer error it wasn't avoided.
I have used both the D800E and D810 considerably, and I find that it boils down to this:
Main reason to go AA-free: Sharpness, and overall drastic image improvement at the level of tight crops. I totally disagree with the predominant opinion that it is an insignificant improvement (see below). I can crop so much smaller areas of the picture and still obtain a sharp result. That's the main factor for me. Even in the photo where Ken Rockwell is trying to show there is almost no difference, I see the opposite, at least a doubling of sharpness. Branches and twigs that look like fuzz in the D800 image suddenly jump out in the D800E image. If you need to crop out one small face from a huge 36 MP file, you'll depend on a D810 or D800E (or 5Ds R) to do the job. You can't post fuzz and keep your job.
Main reason to keep AA: Most of the time it never really matters. Extra sharpness is wasted in 90% or more of the applications of my images. Those who say it is an insignificant difference are talking about these 90% of applications where sharpness doesn't matter that much anyway, and I would agree with them in these cases.
Fake reason to keep AA: Fear of moire.
Moire is something that a photographer can learn to avoid the same as a photographer learns to focus. In fact, focusing itself can be used to control moire. In fact, focusing alone is a much, much bigger issue than moire ever could be.
I lose more photos due to missed focus than I ever will to moire showing up. But do I feel the need to use only f/11 wide angle focus free lenses? Of course not. And the exact same thing holds true about moire and AA filters.
I do not feel the need to blur every pixel in my picture with an AA filter because of a crippling fear of moire, anymore than I need to avoid f/1.4-2.8 lenses because of a crippling fear of being out of focus.
I will always buy the camera option that is AA-free, and with the current state of image processing, I don't even need to feel the slightest bit of anxiety about doing so.