In the past two days I've been notified that the D800E that I had pre-ordered has arrived at two different retailers. I cancelled one and decided to take delivery of the other from B&H. However, I received a D800 from Best Buy over a month ago and have been enjoying it. I really can't justify keeping both cameras. So, what to do? Which would you keep? What would you do with the other? Life's a ####!
My partner, despite being an attorney, shies away from the complexities of photography, preferring a simple point-and-shoot. She used a film SLR years ago, but is now happy with snapshots from her Coolpix. I think she would fire up the old 'evil eye' if I made noises about keeping both cameras.
From everything I have read on this forum, and from my own experience with my D800, I would stick with the D800 that you have. Apparently it is working well. My bet is that you will find it impossible to see any improvement from the D800E.
Remember, whether registered or not, the warranty is not transferable to a subsequent owner, at least not here in the US. If you decide to keep the D800, just return the D800E to B&H for a full refund.
In light of your info on the transferability of warranties, I decided to cancel my D800E order with B&H rather than try to sell it to someone with potential warranty issues. I'm enjoying my D800 as I travel around the western US in our RV. I was beginning to fear that we would get back home in October or November and I still wouldn't have my camera.