This probably won't help much, but either one is fantastic. Both are tied for first on our list of favorite resorts. Here are some things to consider.
Do you like the outdoorsy themeing? If so, then VWL is a great choice. It's cozey and romantic and the Christmas decorations are hard to beat (my favorite of ANY WDW resort--even better than GF--to me, anyway). I've never stayed in the villas there but have stayed at the main lodge twice during Christmastime and absolutely LOVE it.
BWV is fast becoming tops on our list, though, because of it's location. Being so close to EPCOT (our favorite park) and MGM is really nice. The fact that you can walk to each park (although the walk to MGM is a bit far--but doable) is so nice. If you can get a Boardwalk view, that's even better. I also like being so close to the Boardwalk and all it has to offer.
What a neat anniversay surprise (whichever you choose). Have a great trip!