For me, it would depend on a couple of things. First, how late in August are you going. I would not stay at WL before the crowds die down a little. DH and I have stayed at WL at the end of July and will never do so again during the busier times. Pools stayed crowded from early to late, boat lines were long (and hot!!!), and buses often stop at other resorts. Second, what view are you booking? The standard view room views at WL are terrible!! We've even had a waterview room that you had to crane your head to see even a tiny bit of water. Finally, what parks are you planning on visiting? The boat to MK is nice and peaceful...but not terribly quick. We also have found bus service to be slow. That being said, WL is my very favorite resort during the cooler months.
Surprisingly, my kids enjoy CSR more than WL. (They weren't too keen on AKL, so you really can't go by them. BTW, we're all staying at AKL next week despite what the kids say!!) Location is very important here, especially when it's really hot or the weather is bad. This resort is spread out! To me, this is a positive; to dh, not so much. While others on these boards have expressed issues with the bus service at CSR, I've had nothing but very good experiences. My location preference (and everyone has there own for CSR!!!), is Casitas Building 2, ground floor, facing the long fountain. The view from your room is beautiful. The quiet pool is just a hop-skip-and-a-jump away...but far enough to truly appear quiet. Food is nearby. The walk to the pool is a bit long, if you plan on spending much time there. We have Premium APs, so we tend to spend our pool time at the water parks.