Short answer: Yacht Club!
Full disclosure; we're DVC and own at the BCVs so are a little partial to the villas!
Long Answer:
With the YC you are almost guaranteed a full balcony or patio. With the BC those odds are about 50%. In my opinion the YC is a bit more quieter than the BC and offers a more relaxing feel. The BC lobby seems to be a little busier primarily due to the traffic for the Cape May Cafe.
Both resorts have QS options and refillable mug stations in their respective QS locations [BC Marketplace and {YC }The Market at Ale and Compass]. For both resorts you'll have access to a variety of TS dining including the aforementioned Cape May Cafe [Buffet], Yachtsman Steakhouse, and Ale and Compass Restaurant. There is also Beaches and Cream. Lounges are plentiful, with Crews Cup [YC], Ale and Compass Lounge [YC] and Martha Vineyard Lounge [I'll call that BC side]. Last but not least is another QS option at SAB, actually just outside of SAB with Hurricane Hannas.
As previously mentioned by another poster, bus service advantage goes to YC as it's the first pickup to AK, MK, and DS and shares with BC. Walking is your friend for Epcot and HS, although I know that the walking option doesn't work well for everyone. I personally am looking forward to riding the new Skyliner "just because" on our next visit on October. May even the long way from IG to HS!
Bottom line, you can't go wrong with either resort but to me the YC has few advantages as mentioned above.
Regardless of your choice you'll have a great celebratory vacation!