Are you driving? Parking at SSR is much easier than at the BWV. You park closer to your villa with multiple parking lots vs one large parking lot at BW where you might have to fight for parking with the people looking to park for free for Epcot and Disney Studios.
Are you into the Pleasure Island scene? Then SSR is within walking distance and at BWV you will have to drive or take the bus. BWV has the piano bar and one other venue for adults. But you are within walking distance to Epcot and Disney Studios.
SSR is newer than BWV.
SSR has two themed pools and at least two other non-themed pools. BWV has one themed pool (with the scary clown that regurgitates you when you use the slide) and one non-themed pool on the villas side. I think you can also use the pool on the BWI side (also non-themed).
BWV has the BW shopping venue, while SSR has the DTD shopping venue.
BWV has a few dining opportunities on the BW or via the other hotels there, plus the Epcot World Showcase dining (if you have the park ticket to enter). SSR has Artists Palette (upscale counter service), the turf club (table service), plus the DTD dining venues. Both will have a nearly identical kitchen.
Disney Transportation - all buses at SSR with multiple stops at the resort vs boat or walk to Epcot and Disney Studios, bus to AK and MK with one stop shared with Swan/Dolphin.
BWV is set up as a hotel like resort = one building. SSR is set up like a community resort = multiple buildings.
Personally, I've stayed at the BWV once and won't do it again. I've stayed at SSR twice and would do it again in a heartbeat. And we love OKW.