I'd guide on their interests.
Agreed! My kids will usually tell me what they want to do in the summer, then we look for camps/courses in these areas. DD9 so far has signed up for a math camp, a science camp, a theatre camp, a music camp, and a couple of leisure/sports camps, and she will keep dancing in the summer as well. DS13 signed up a music camp, and most likely will do an online AP course in economics, and then he will sign up to do some local volunteering work.
I think what parents really need to pay attention to is whether the *level* of the camp will fit with the kids. I call the camps before we sign up and let them know what we are looking for and ask how they accommodate students who are way above their age peers' levels. Some people will be quite happy to let me know that they look forward to having such kids and they have ways to challenge them. Others will give you standard answers such as "we encourage team work and social interactions so all kids will do age appropriate activities" etc. Then you know which camp not to sign up for!