I did a British version in 2008 and through that know lots of people who did Camp America. They loved it, one person went back year after year, others then went on to travel around America a bit before coming back.
I was a seasonal worker for 3 years, it's a fun lifestyle but tiring. Obviously doing a "short" stint is different though but:
Never believe the sales pitch. It might be an awesome experience, but they tell you what they can to get you there.
Once there the higher ups don't really care too much. A few times I've known people in activity work get injured or ill (beyond a couple of days off type thing) and they're sent home because they're taking up a bed that a worker could use, which makes sense but when you're not expecting it, it's not nice! Check what happens in those situations, especially if they're going to be abroad! It's rare for it to happen but two badly broken bones happened to staff on one of my seasons, two of the Brits thankfully so they did have homes to go to that weren't too far away!
The hours are long and the work can be difficult, it doesn't suit everybody.
You are going to be around children, whilst you don't need to love them, you need to be able to curb swearing/bad language around them ;)
I'd totally do another season at a kids camp though, it was a big party outside of work, lots of craziness, lots of dressing up (both whilst working and not!) and odd drinking games! I got to meet so many interesting people and am still in touch with a few of them, mostly Aussies but there are a couple of Brits who I see occasionally too which is nice :)
There are one or two American-based camps who used to make its workers sleep in a room with kids, if that's an issue do double check sleeping arrangements. A friend of mine ended up over there and only found out once they started working, it was something that made him very uncomfortable.