No personal experience, but these programs are popular among a certain subset of students here.
DD, now a senior, has one older friend who attended one of these programs at different colleges every summer from 7th grade on. She personally was not overly enthusiastic, but it sounds like the whole thing was more her parents’ plan, if you get my drift. She at times ended up taking classes she wasn’t totally interested in, and seemed kind of burned out by senior year, though that is not unusual here. I can’t say if it affected her eventual college admissions; she is at an Ivy League school, but might have ended up there anyway, who can say? (I am not sure if she attended a program at her current university, but the last couple of summers, arguably the ones that might matter according to some, were at different schools).
DD has another friend who attended a summer program, in a field he is very interested in, at a highly elite school he very much wanted to attend. He had a great experience, and was admitted there early decision.
