We have stayed at I-Drive for years and I cannot say enough good things about the rec staff and all the activities they offer around the pool. Absolutely outstanding!!
With that said, however, the physical pool arrangement at PS is far superior for your kids. They have a pool slide, zero entry, much bigger pool and, like I-Drive, offer lots of organized activities. It is slightly closer to Disney although both sites are really close. But if the pool experience is a big factor, I would most definitely go with PS.