Depends on how much $, how long you will be at WDW, and how much you are in your rooms.
We have stayed at CSR and ASMo.
I enjoyed both, but I actually liked ASMo better.

DH liked CSR better.
Just a matter of personal taste and each have pluses over the other.
CSR is a very quiet resort. (As was ASMo for us, but we were there in January on both trips too.)
Nicer food court and grounds at CSR. (No doubt)
More recreational activities offered at CSR. Nicer pool, hot tub (spa), a fitnness center, a laundry facility that is relaxing (as opposed to ASMO which is small, busy and stressful).
ASMo is a real kick

(I want a four story high Buzz next to MY house). ASMo was also quiet for us, immaculate grounds, FRIENDLIER and more efficient CM's (from our experience) and CHEAPER!
I would be happy at either.
Tough choice. Let us know what you decide.