I've stayed at AS Sports (twice), AS Music, Pop (too many times to count), POFQ (multiple times), PORS, CBR, CSR (four times), AKL, WL, and BW. By far the best bus service we've ever gotten has been every time we've stayed at CSR.
In fact, I originally had my upcoming May trip booked at PORS and switched to CSR mainly because of their great bus service. Due to it being a convention resort, conventioneers are in meetings all day leaving the buses free. Buses come frequently and I've never had to stand on a bus in the mornings. At night, the only time we've had to stand is if we leave the parks late and that was just once.