CSR is a convention resort, which means that you may have a very busy food court in the morning when conventioneers are getting ready for their conferences and at night when the conferences are over. The biggest drawback for us is that the rooms only have one sink, which with 3 adults, could be a bit inconvenient. The pool is nice and large with a very nice slide. The Cabanas section is very nice and quite beautiful. They are also very convenient to both the main building (closest building is 9B) and the themed pool (closest building is 8A). Most of those who are there for conventions are located near the convention hall in the Casitas.
The Caribbean Beach Resort is very spread out, and the only drawback we saw was the fact that the check in was located across the property from the food court and restaurant. The pool is nice, though not as big as that at the CSR. Rooms at Martinique are very convenient to the food court/main pool building, but we prefer those in Jamaica, which is across the bridge from the food court, etc... about a 5 minute walk. This is usually the 1st bus stop, so you can usually get a seat on the bus, and you will be the 1st dropped off. If you don't relish walking too far to the food court, do not request Barbados or Trinidad South. The beach is quite beautiful and the hammocks are very relaxing. You can usually see the high fireworks from Illuminations at night from the Beach. The entire resort has been refurbished within the past 3 years, with very nice results. The rooms are also the largest of all of the moderate resorts.
Port Orleans Riverside is one of my favorite, so I might get a little biased here. We love the theming and the relaxing atmosphere. We also love that we have the use of 2 themed pools, the boats to DTD, 2 food courts and a butterfly garden located behind Arcadian House. Our favorite buildings are Alligator Bayou, bldg 14 or Parterre Place in Magnolia Bend, both of which are extremely close to the main building and bus stop, but still have the feeling of being in either Bayou country, with its rustic charm, or the old south, with its plantations. We also love the live entertainment in the resort lounge 4 nights a week. We think, of the resorts that rely on bus service, that the Port Orleans resorts have some of the best, no matter which park you want to frequent.
Whichever you decide, I hope you have a great vacation, and we can't wait to hear which resort your picked!