We have stayed in all 3 of them.
With all adults, I second OKW for the space.
There is the boat--which will avoid all that weekend traffic there-- & bus to DTD.
Love the full size washer/dryer & the built in buffet-great for recharging cameras, cell phones etc (just remember to bring your Squid!). The kitchen is much larger and can accomodate 2 cooks, easily.
We will do BCV or BWV when our group is all adult for the ease of all the dining venues & the short walk to Epcot & MGM.
FIL likes to roam early in the morning, on the prowl for coffee & sweets, so the Epcot area is ideal for him. Plus he has no idea how the WDW transportation functions, so he can be up & off to Epcot & MGM without anyone having to accompany him. We're a family that will tour in packs or go it alone!
SSR is roomy and has the boat to DTD. Am not a big SSR fan, but many are.
The Grand Villas are HUGE, perfect for a group.
Jean