I think the other posters have given you some good guidelines. If you spend a lot of time in your room on vacation, where a smaller space may be a negative, then OKW is probably the way to go, as they are the roomiest. However, if the location is what's important to you, then I would say BCV would be your best bet.
I am an OKW owner, and I love the relaxed feel of the resort, and the spaciousness of the actual units. We don't spend a lot of time in the room, since it's just DH and I, but when we are there, it is nice to be able to "spread out". If you have smaller children, who might be napping midday or whatever, room size might be more of a consideration. We have stayed in a 2BR at OKW with 5 not petite adults, and have felt like it had a lot of room, and were not at all cramped.
That being said, we same 5 not petite adults have also stayed at the BWV, which I think are going to be similar to the BCV in their size and layout, judging from the preliminary things I've seen. I must say, while I didn't feel cramped in the 2 BR unit, I did notice that it was smaller than OKW. Again, each of them has their plusses and minuses.
DH and I just returned from WDW,stayed at OKW in a 1BR. Moseyed over BCV, but they wouldn't let us into the construction area. DH did bring up one point. Ariel's Restaurant(at the BC)and the Yacht Club Galley(at the YC)are both closed. CMs we spoke to at the BC said they had no idea when or if the restaurants would reopen. DH felt that when the BCV do open, the lack of restaurants at the YC/BC might be a problem. Now of course, there are many restaurants within walking distnace at the BW, so maybe it won't be as much of an issue as DH thinks. Just a point I thought I'd bring up.