I have stayed at the FS CR as well as Hualalai; I've been to, but not stayed at, the FS Maui.
We really liked the FS CR. It is relatively small and the rooms have screened in porches that were great for just hanging out. It is at the very end of the peninsula, so there are beaches on two sides; the beaches are well maintained, the water is warm, and it is easy to swim in. The pools are well maintained and I liked the grounds very much. Excellent spa. There are activities similar to other FS, including a pretty interesting nature tour of the golf course (the course is stunning itself). There are animals, including various birds and monkeys, on the property.
I would agree that much of the charm of CR is being able to do lots of activities (rafting, hiking, going to the volcanos) pretty easily, but I do think the FS CR delivers a very good resort experience. It is fairly isolated, so if you think you will want to eat a lot of meals off property, take that into account.
I love the Hualalei, and think it's fantastic. It certainly is very set up for kids, with the dedicated pool area. The lack of a swimmable beach is a negative, but the property is so beautiful that it can overcome that. The large number and choices of pools also help. Also, for a child over five or so, the Kings Pool (essentially an enclosed snorkel spot) is awesome. It's like swimming in a big aquarium. On the other hand, the Hualalei is (at my last check) very very much more pricy than the FS CR. Depending where you are, it may be quicker to get to CR than to Hualalei, also.