As a gymnast I went to camp at IGC, Parkettes, and a college camp at WVU. They all provided really different things and some I liked better than others. IGC had a lot of fun stuff to do, the gyms were huge, and some of the coaches were great. The downside was that some of the coaches were not so great. They put you in a group with kids your own age and skill level though which was good. Parkettes was a bad experience overall, just wasn't the right fit for me. The groups were done by level alone, so as an 11 year old level 5 I had lots of younger kids with me. You stay with host families there and I was with a family with a very high level gymnast daughter and the other camper there was also a very high level gymnast, I didn't quite fit in as an older level 5. I was also sick when I went, so maybe if I tried again another year it would have been better. WVU was my best camp experience. I was older and knew what I wanted out of camp. The coaches were great, the gym was awesome, I was with some really great girls who were my own age and skill level and pretty low key. There was lots of gymnastics and not all the extraneous stuff like at IGC which I loved. There were fun activities too, but it was more gymnastics focused. The coaches really cared about you and wanted to see you do well and I learned a lot. It was a great experience and my favorite camp.
I worked at Flip Fest after my competitive gymnastics days were over and it was a lot of fun. Great gym, great cabins, lots of fun activities in and out of the gym, an awesome ropes course, fun coaches who also know a ton, just a fun place. Probably less structured outside of the in-gym time than other camps, but still fun. The atmosphere is pretty casual and the guest Olympians are very approachable. Sometimes they eat meals with the campers, play games with them, actively coach, etc. so different than other camps where they are around just to provide a quick bit of encouragement or sign an autograph. And John Roethlisberger is just about the nicest guy you could ever meet. I transfered to a college pretty far away after my working experience there but hope to go back after I graduate to coach.
So I think they can be a good experience, just be sure to look around and find the one that's best for you. Some kids do better at smaller camps, others really have a great time at the bigger ones. It all depends on the kid and what they want to get out of the experience.