We've done a few gifted summer programs with my kids like Yunasa and a summer camp through our local talent search, but not JH's CTY camps or SIG. I will say, though, that we looked at SIG and it has been discussed here before just maybe not in comparison to CTY. When I've seen people discuss CTY here, the reviews all or mostly seem to be pretty positive. I've seen a bit more mixed reviews on SIG.
I can't recall, but doesn't SIG have a more open admission policy than CTY camps? In general, when dealing with kids who are more than "garden level gifted" (i.e. beyond say the top 5% or so of age or grade peers), I tend to find that the more restrictive or higher the admissions standards, the more likely the program is to be a fit for the child. It really sounds like you have a child who is beyond my definition of garden level giftedness.
