We have recently stayed in both (cbr in April and CSR in June). We really enjoyed both resorts but they are very different and each may suit different families better.
I guess I will start with cbr. We went into this resort with very low expectations and came out very much in love with it. It is large and spread out for sure (as are many other WDW resorts) and I believe that it's size is greatly exaggerated on these boards. We stayed in Trinidad south in the furthest building from the amenities and it was a 7-10 minute walk maximum. We were also the last bus stop and had zero problems with transportation. With two toddlers and a double stroller I had to have a seat and had no problems. There was a cm stationed at the bus stop in the morning calling dispatch for more buses and after talking to her, it seems this was common. The pool area was fantastic. I cannot say enough about it. Two water slides and a great gated in kids play area (for the 48" and under crowd which they did enforce). The grounds were so beautiful. Pictures didn't do the resort justice. Our room was immaculate and beds were reasonably comfortable.
What we didn't like about cbr, well, not much. The food court is just that, pretty standard. We don't eat breakfast at food courts so we just had a dinner or lunch a few times. The TS restaurant looked about average.
We went into CSR with high expectations after seeing so many people on these boards refer to it as a "deluxe light". It didn't disappoint but to me, it's still a moderate resort. The rooms are beautiful and as a pp stated all have queen beds to cbr's full size. It certainly doesn't feel as WDW on the inside but the room is very pretty. Housekeeping was fantastic, another immaculate room. What really took us by surprise here was the food. We like Mexican food a lot. The pepper market had all the usual items and some Mexican items as well. I also liked that you did not pay for your food until after you ate so no standing in those long food court lines with the food getting cold. We also tried the TS restaurant and to our surprise, it was one of the best meals we have ever had on WDW property (and I think the food at WDW is waaaaayyy overrated). Bus service was good but we were the first stop. By the time we got to the third and fourth stops it was standing room only and the driver was dispatching for more buses. Had I been staying in the cabanas section I might have another view
What we didn't like about CSR is the pool. It gets a ton of love on these boards and I really don't get it. I understand the slide is good but the rest of the pool was disappointing. The toddler play area was pitiful. The pool has no zero entry and is overall pretty deep. For us, it wasn't great for our younger kids. My DH didn't think the grounds were that great (I did) and only liked the rancheros section (since nobody else does maybe he is weird). I did like the rancheros a lot too.
I can't help with an opinion on a preferred room at cbr as I stayed in about as far way from preferred as you can get. We loved our pirate room though. It would, IMO, be convenient to stay preferred here if you like the refillable mugs and rely a lot on the food court. As for CSR, we did stay preferred and to me, CSR is a little tricky. We did not pay for a preferred but were upgraded to a water view room in one of the casita buildings, 2 I think. The preferred rooms are generally the first bus stop (as well as casitas 4 and 5 which are standard) and are the closest to the food areas. They are not close to the main pool so that is the trade off.
For us, if we stay at another moderate resort it will be cbr for sure. We loved the pool area, the grounds, and loved the pirate room (although I have a Nemo lover so the regular rooms would be good too). If we were to go as just adults or of our kids were older I would prefer CSR. Hope this helps a little bit. It's a hard choice but for us, they were both fantastic and I think no matter which you pick you will love it.
