I have stayed at both, and both are great.
First, I would ask if you plan to spend more time in Epcot or spend your time evenly between the parks. If you plan to spend more time in Epcot, BCV is a shorter walk (not by a lot though) so it might be more convenient. Also, if you are driving, the parking is closer at BCV than at BWV. BWV is the only resort where I always get luggage assistance because of the location of the parking lot.
As far as the rooms themselves, they are virtually the same in size, layout, and decorated in pastel colors. There is a coffee table at BCV in the studios that BWV does not have, if that makes a difference to you.
The views at BWV are nicer, in my opinion, because most of the cash reservation rooms overlook either the quiet pool or the feature pool, with the waterway to the Studios and S/D in the background. There really aren't any great views at BCV. I've overlooked the quiet pool, the road, and the woods.
I have had two vacations at BCV this year and two at BWV, so you can see that I like them pretty much evenly. I don't think you can really make a bad decision between them.