We've stayed at POFQ (pre-merger w/Riverside), CBR and CSR (as well as CR, WL and ASSp).
First of all, I don't think you can go wrong with any of these. I don't think you can beat the combination of price and atmosphere.
My personal preference is CSR. Pros--beautifully landscaped, great pool, Pepper Market (selection of food, real silverware and plates). Cons--can be a long way from El Centro (check-in, food court) (but bus stops at every section, and pool is close to Ranchos section, and quiet pools in each section), 10% added at Pepper Market (never bothered us, they'll take it off if you complain). Some complain about conventioneers, but we haven't really noticed them in three visits.
CBR--Pros: Recently renovated bright rooms, rooms larger than other moderates, nice stroll around lake and island. Cons--can be long distance to Port Royale (main pool and food court)(but quiet pool in each section), smallest main pool at moderates (relative to resort size). Haven't been since they renovated the food court and sit-down restaurant.
POFQ--Pros: Nice theming, great pool (particularly for kids), smallest moderate, boat to Downtown Disney. Cons: no sit-down restaurant (have to go to Riverside), small size makes it a little less immersive than CSR or CBR (but you can stroll over to and around Riverside)