We've had experience with CITY/CBK, CTY and TIP. Please note that each year these programs evolve so some info is old. Oldest DS says his hardest summer was CITY/CBK 3 weeks in Denver when they used to offer 2 courses. Now CBK 3 wk program is held at Colorado School of Mines in Golden and many of the courses sound very high-tech (whereas they were more varied at the Denver campus). I do not doubt the challenge level at School of Mines. My two youngest DS's have done the one-wk program for 4th-6th graders and enjoyed them, but for all the effort of getting them there and back, one week is too short.
One DS took CTY's Stanford program for 5th and 6th graders and loved it (he's the hardest to please and to challenge). Highly recommended. We've also done JHU CAA (Santa Cruz)- second DS's favorite program to date. He did CTY JHU campus which was his most challenging to date. One DS did CTY's oceanography in Hawaii and enjoyed it thoroughly. One did CTY's F&M campus and enjoyed it.
Oldest did Duke TIP East Campus and loved the course, though he said it wasn't as hard as CITY/CBK. Second did Duke TIP Davidson and said it wasn't as good as JHU CAA.
Summary: for folks who are not close, I'd wait to do a 3 wk program (CTY over CITY/CBK for younger students). After that, it's a toss up and I encourage the kids to pick a course that they're passionate about or that's outside their area of knowledge (so they learn something new). I also try to pick a campus that would be on our college tour (Duke, Davidson, Stanford, etc.) and move into pre-college programs sophomore or junior year.
