Having stayed at both POR and CSR, I have a few answers to your questions. We stayed two times at POR before we finally decided to stay at CSR. My family loved POR. They love the theming and food court at POR. Then we stayed CSR and now everyone loves CSR. We all like the food court layout so much better. Once you understand the system, it really makes sense. We just got back from a quick trip and stayed at POP and we all talked about how we wish all the resort food courts would go to CSR system. At POP, you would stand in line for 10 minutes to pay for you food and if you want anything else, you need to stand in that line another 10 minutes. However, at CSR you can go get something, have your card stamped, eat and go back and get some more fruit, ice cream, or a cookie for the kids. You only have to stand in line to pay(and we rarly stood in line) once.
The pool at CSR is fantastic. My kids did not want to leave it to go to a water park.
Bus service at CSR is among the best. POR usually shares with french quarters and the bus lines are usually long. Keep in mind if a convention is going on at CSR, most of the convention goers will not be on the bus in the morning since they will be at meetings. And in the evenings it seems like most convention goers spend the evening relaxing at the pool or Downtown Disney. The bus lines for CSR are usually not as crowded as other resorts. For our stay at POP, the lines were LONG - wait for 2 - 3 buses in the evening. After the fireworks at the MK, we waited for 5 buses before we got a bus.
Either resort is good. But, I would pick CSR.