Grainger is really the only convention that takes over the whole resort. They have been doing it for years. They pretty much take up all three sections of the resort.
We find the mattresses to be terrific at CSR but hate the pillows at all the WDW resorts. They are way to small if you are used to large pillows or body pillows.
I've stayed at both and definitely prefer CSR. The pool is much better and they offer the movies, campfire and daily pool activities for the kids. The arcade is also there along with the playground. Its just perfect.