I have stayed at all three of them, and all of them are very nice with their own pros and cons. Out of the three, my favorite is the POR. It seems a bit more peaceful than the other moderates to me. If you plan on spending time at Downtown Disney, there is a boat that goes there, which is fun and convienient. You can also get a room with a trundle bed, which would allow five people to sleep in the room. In the CBR and the CSR, there can only be four in a room.
The CBR is my second favorite out fo those three. I just stayed there for a couple of nights last month (me second stay there). It seems a bit more spread out than the other moderate resorts. I don't like that the guest relations and check in area is seperate from the rest of the resort.
The CSR is also a beautiful resort, but there were a couple of things about it that keep me from returning there. The rooms don't seem as soundproof as the other moderates. We could hear our neighbors TV and talking (and they weren't yelling or anything). We could hear the footsteps of the people in the room above us. I never heard a neighbor at the other moderates. I also do not like the way they run the food court at the CSR. They have a host who seats you, will get your drink for you, and clears your table. You get your own food. For the services of the hosts, they tack on 10% to your bill. With a family of five, that will really add up.
All that being said, my favorite moderate is the Port Orleans French Quarter, and when that reopens, it will be hard for me to stay anywhere else. I find the size of this resort a lot more managable, and the pool is fantastic. I have stayed at this resort more than any other resort on Disney property (I've stayed about about 10 different resorts over the years), and this is the only one I've been completely satisfied with.
Karen