Who is in your group and would you be renting a studio, 1BR or a 2BR? We switched our June reservation from a junior suite at CSR to a 2 BR at BWV (we rented points). The room was great with plenty of space, a full kitchen, and a washer and dryer (which came in handy when we got caught in the rain). We had five in our group - me, DH, our two DDs, and DD13's best friend. For the four of us, we would rent a one BR, but I would rather be in a room at CSR than in a studio since CSR has two queen beds and a BWV studio is one queen and a pullout sofa. I will say that the kids found the pullouts at BWV to be very comfortable, but I don't find the studios to be better than a regular resort room.
The beds at CSR and at BWV are both very comfortable. The kids liked the pool and slide at CSR much better. That might not matter to you for a January trip. We enjoyed walking to Epcot and walking or taking the boat to DHS. We drove to AK, and we drove some and used the buses some for MK. I preferred to drive to MK from BWV since the bus stopped at several resorts.
BWV is DH's new favorite resort, partly because he loves the Epcot area (previous favorite was Beach Club) and partly because we were spoiled with 2 bedrooms and 2 bathrooms.
Paying cash, I would pick CSR every time for the value for the price paid - it has everything we want in a resort at a great price. If you can rent points for a 1 BR or a 2BR, I think you will really enjoy BWV. You probably know that renting is much less flexible in terms of canceling or changing dates and you don't get daily housekeeping. If you can find a rental at a good rate and can live with the rental terms, it is a great value.