All of the moderates are a nice choice. It just depends on what your preferences are.
All three are beautiful resorts and all three are spread out. This is a good thing because they are all three easy to get around in and since they are spread out, they are very quiet.
The transportation for all three moderates is similar. There are some differences, but nothing major or worth ruling one of them out or making one of them better than the others.
CSR has the nicest main pool and several private pools - one in each section. The resort is beautiful. The room size is the same as the PO resort, but a little smaller than CBR. The biggest issue for 3 adults at this resort is that it only has one sink. If that isn't an issue for your party, then it won't be a problem. The food court here is a little different than the other moderates. Some people like it some people don't. We liked the other two food courts better, but I wouldn't let the food court keep you from staying here. This is also the only moderate that has a salon and gym. If those are amenities you want, then this would be your choice.
CBR is also beautiful. It has the largest rooms, by a little, of the moderates and does have two sinks. It also has a themed main pool and each section has it's own private pool. One plus for this resort is that you can see the higher fireworks at EPCOT from several spots in the resort.
PO is a beautiful resort. The rooms are the same size as CSR but you do get the double sinks. It also has the main themed pool and several private pools. We felt that this resort had the most peaceful private pools, but the other two were very satisfactory as well. This resort does have the boat to downtown disney and also has the nighttime entertainment in the form of the live music.
We have stayed at all three of the moderates and our first choice is PO, our second is CBR and our third is CSR. That doesn't mean that we did not like CSR. It just meant that we liked the other two better. That opinion is not gospel and is only based on our likes/dislikes/experiences.
I really don't think you would go wrong with any of them.
