We have been to Key Lime Cove, Kalahari and the Wilderness. They are all a bit different and it depends on what you are looking for. Key Lime Cove is very bright and has a great "island" theme and the rooms are very nice as well. The waterpark is large and there are lots of activities going on around the hotel. It is also close by for you being in IL. The Kalahari also has a nice waterpark but they also have a very large game/activity area with a high ropes course, go karts, laser tag, lots to do check it out on-line. The Wilderness is also nice and they have more than one indoor waterpark to go to so you can get a change of scenery but the waterparks are pretty similar. I would suggest going to Key Lime Cove in the winter and then going to the Dells in the summer when you can enjoy the outdoor waterparks as well. Once you bring the kids to a waterpark they will be begging to go again!