I asked the same question on this board several months ago but didn't get very many responses.
We've chosen a 2BR at BCV. I had waitlisted for both BWV and BCV and had BWV come through first. I stayed on the waitlist at BCV just in case. It came through, and then we had to choose. Isn't that such a horrible choice to make?
Anyway, we've stayed at BWI before but never BWV or BCV.
So, we chose BCV because:
1) We've never stayed there before and we'd already tried BWI
2) The pool sounds really neat (although we're going in late Nov/early Dec and may not be able to use it)
3) Liked the idea of being closer to EPCOT
I'm not sure when you're going but if it's for the trip that's in less than a month (judging from your ticker), I'd say waitlist at both and take whichever comes up but definitely go for a 2BR if the grandparents are coming along.

If both are available, go for BCV. I think your kids would really enjoy the pool.