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.

I went to the Ballroom Vermont dance camp last week of July. It was very well done. They divided the dancers into 4 levels, from absolute beginner (depending on the dance) through "gold" altho my impression was that the steps they taught in gold were really Silver-ish. The classes were taught very well, the coordination of the lessons was very good, etc... Not for competitors, but terrific for anyone who wants to spend a great week learning new steps, improving technique, and enjoying a lot of dancing.

An example: they taught a nice variation including fallaway and slip pivot, in the foxtrot, waltz, and tango classes. The work in one class was carried over to the other. Likewise oversway with a ronde arabesque "out" in waltz and tango; lots of crossovers.

Highly recommended.