I've stayed at both and prefer CBR. I love the tropical theme. I wasn't crazy about CSR's food court. I always get a rental car, so distance isn't an issue. I stayed in Martinique once and Barbados twice. Can't remember which building at CSR, you turned right after you entered, it was by a quiet pool.
....would not stay at CBR again. There are just too many bus stops at CBR and it seems to take forever. It always felt crowded and a far walk. I too remember dragging all of the luggage up the stairs. We found CSR beautiful, and loved strolling around the lake. Because of the conventioners, the busses were never crowded. We tried to stay there last time, but it was already booked.