Well, I'm not sure if AKL is worth $268 because I've never stayed there! I would like to someday though.
I would rank your three choices: Caribbean, Riverside, then Coronado.
CBR is my favorite! The theme is great--it's so bright, fun, and tropical. The main pool was just renovated, and so were the rooms (they now have nemo and pirate themes). Plus, while it is a very large resort, it is the only one of your three choices to offer an internal shuttle-- so if your room is far away, and you don't feel like walking to breakfast, you can just hop the bus to take you there! Plus CBR has at least six quiet pools! It's a great resort.
POR would be my next choice of the three-- I do like this resort, but it's not a favorite. I like that it offers the boat to Dowtown Disney, plus the food court here is great! The theme is a little boring for me though, and it is a large resort but does not offer an internal shuttle like CBR does. Riverside is not a bad choice by any means, I would definitely return there, but it just wouldn't be my first pick.
CSR was a problem for us-- We found the Pepper Market food court to be very expensive (we were not on the dining plan) and inconvenient. From our experience, we found the workers to be very rude. And we just didn't care for the whole feel of the resort-- it seemed to be lacking that Disney magic that all of the other resorts we've stayed at have.
Good luck with wherever you choose, and have a great trip!!