Are you traveling with kids? If you are, I'd go for the Polynesian for the resmaining 6 nights. Monorail access, great theming, close to MK, walk to TTC and from there you can go anywhere. Plus great new pool, etc. You know all about it!
If you aren't going with kids, go for the Yacht Club. The Beach Club is just as nice, but attracts mostly families with small children. The Yacht Club (I stayed there with my husband and no kids and we LOVED it) is beautiful, nice large rooms, great garden views, excellent restaurant on site, plus we walked to Epcot every night for dinner. You are also near the BoardWalk to enjoy the night life there. The pool there is gorgeous. The one drawback is that you have to take a bus to the Magic Kingdom, and it's simply a long journey with young children-- to and from. If we weren't going with a 2 year old this week, we'd have gone back to the Yacht Club. I'm sure you'd love it. Just make sure that you know what kind of room you are getting-- I read somewhere else that someone ended up with a small room with a Murphy bed (!! I didn't know any Disney resort would do this, esp. a luxury resort-- but maybe it was a connecting room for families that wanted a living room space in the daytime, who knows). My room had 2 queen beds (that's what you want-- or a king) and it was so nice. I think that the Yacht Club also has 24 hour room service, which is a little bit better than the Polynesian, that stops at midnight. you also will run into fewer famillies at teh Yacht Club. It is a more sophisticated setting, sort of like a laid-back Grand Floridian.
Sorry to ramble-- hope this helps!!!