Having used buses extensively at both SSR and BWV, I can say that I will avoid buses at BWV any time I can. The only worst bus experience I've had is Pop Century (because of numbers). For me, the frequency isn't the issue - it's the stops at Swan, Dolphin, Yacht Club, and Beach Club that really drag the trip out.
SSR seems to be much quicker, even though you still have 3-4 stops in the resort itself. (Big difference picking people up at several spots in same resort, versus visiting different resorts. The stops are shorter and much closer together.)
I don't know how it is in the afternoon slow times, but the morning schedule at BWV seem to have the MK bus starting at BW, then going to swan, Dolphin and MK. The morning AK bus was hitting all 5 resorts last May, don't know if that has changed with AK's increased popularity. Haven't tried the Downtown Disney bus, but I imagine it would stop at all 5 resorts, too.
Dirk