Bassetlover - I only know one person who did the Institutes program, and that was several years ago. I think it is a little less intense, and may bring in some kids who otherwise wouldn't qualify for the summer programs - there are no hard cutoff scores like the Center/Academy programs. They are also shorter in length from what I see- 2 weeks vs. 3 weeks for Center/Academy. The Institutes offers some interesting locations, too.

I think the difficulty varies with the individual class, not the program (CTY vs TIP specifically). My D's roommate at TIP took a writing class and spent her free time socializing, while D studied for the tests that were given almost every other day. To me, it comes down to location and specific classes that interest my kids.