What are the most recommended workshops in the U.S. aside from the BYU summer camp?

I think there is one in las vegas in the summer time... but don't take my word for it, try checking dancevision.com

I am planning to go to one at Killington, VT, in a week, but I have no experience with it yet.

I've been to dance weekends by Stardust in the Catskills, and I have not liked them. They were too crowded and undisciplined. e.g. When beginners stayed in the advanced classes, the instructors started teaching them from scratch, destroying the class.

The BYU camp is great, partly because each class spans several days with the same material, and the learning builds over time. This is far superior to other formats where there is no continuity.