My guess is that the issue here is the on-board WiFi. If AD2019's post is correct, then what other reason could there be?
My current decision is to go with the A8N-SLI Premium board, however, if the A8N-E Premium comes out before or at the same time, then I'll go with it. Maybe some new information will come out at CeBIT. I'll most likely have to decide in the next week now, as my case requires me to specify the motherboard before it's finished being built, as the video card uses heat pipes to be cooled. Unfortunately, ASUS puts the primary video card (PCI-E 16x) in the top slot on the SLI board, but on the non-SLI boards, the 16x slot is located on the 4th (or last PCI-E) slot on the board, or near the middle of the board. If ASUS would have kept both as the top slot, then I could specify either as being okay, as the boards seem to be very close in the location of the PCI-E slots, then I could wait another two weeks until buying the board...