Well, the only place I could even find any mention of a "Premium" A8N-E is over at Overclockers UK
Text ... there's no mention of a "Premium" version on ASUS's website (in fact, the USA one doesn't even list an A8N other than the SLI ones ...), just the
regular A8N-E
That being said, here's the differences I could find between the two:
The Premium appears to have 4 more SATA ports than the vanilla
The Premium appears to have 1 more GbE port than the vanilla
The Premium appears to have a 802.11g wireless
Other than that, I don't really know. Seeing as how the Premium is on "preorder" over at OCUK, and I can't find any other mention of it, that version of the board might not even show up in retail shelves anywhere ...
HTH