Never, but I did go to Guitar week several years ago. It's the best set up I have seen at any camp or workshop. You have a morning lesson each day with your chosen teacher. Each morning, they build on what went before, correcting mistakes as you go. They have a week to really impart some knowledge. PM classes you can choose a different teacher each day, or go practice the mornings lesson, sleep so you can stay up late jamming, etc. The teacher and classmates get very familiar by weeks end. I still correspond with my guitar teacher from 6 or 7 years ago, and am hoping to set up a lesson next month, when our passes will cross for a few days. It spoiled me for the 1 hour classes at festivals & such. Now I take very few of them, and just find someone to jam with instead.