I have stayed at all of them and POR is my favorite!
The grounds are simply beautiful, so lush & tranquil.
Excellent food court.
Fun pool, several quiet pools as well.
Boat to Dowtown Disney is nice.
Rooms are currently under renovation.
My 2nd favorite is POFQ, compact & quaint. Good food court. I don't love the rooms as much since the recent refurb & the pool is cute but may seem "babyish" to kids over 5 or so.
CSR, really lovely resort but during my last two stays here it was overrun w/convention goers. I didn't care for any of the food offerings. CRS does have a fantastic pool & very nice guest rooms.
CBR, the resort itself is very appealing & lively. I thought the guest rooms were rather bland. I found the food court just *okay* , we didn't try the full service restaurant (shutters?). The pool at CBR is a lot of fun, my kids really enjoyed it.
I can't really speak to the quality of bus service at any of the resorts as we always rent a car.