I have stayed at 3 of the 4 mods. And have spent time at the 4th. Here's my take.
CBR wins hands down for me. It may be large, but the walks are nothing. We stayed in the very furthest building in Trinidad South and still had under a 5 minute walk. There is so much to do there. It has great relaxing spots (hammocks on the beaches, quiet pools, etc). It is very inviting. Truly feels like a vacation. Great bus service. They have an internal, plus there is a stop at each village.
Next choice would be POR. Very relaxed. Pool area is great. Boat to DTD. Decent food court. Great restaurant.
Next is POFQ. I liked the smallness of it (this is the one I haven't stayed at). Food court was lacking and no sit down restaurant. Only 1 bus stop. Can get crowded.
Last on my list is CSR. We stayed here May 06. While the resort is pretty, the Pepper Market and Maya Grill were over rated and over priced. Both were absolute madhouses. Makes it hard to get a family dinner (at PM), as you are waiting in this line for this persons food, then you have to go stand in this line for that persons. The place is huge. We were in one of the buildings near the main area (El Centro, I think??) and had a LONG walk to the main pool. The place gave off a cold vibe to me. Too many conventioners and people in suits. I felt like I was at a chain resort (Hilton, Radisson, etc) instead of at Disney. I personally didn't think it was geared towards kids at all. More the teen segment if anything. I will give it credit for being beautiful.
All that being said, we are going back in 16 months and I am going between CBR and WL. Time will tell..