Best clinics… between John Turner, Claudia Cojocar, Micheal Patrick, and Detrich Von Hopfgarten. First three are/where h/j, last one was dressage (when I was a kid, he was available for non-dressage specialists). All are/were entertaining, fun, and on point for learning and advancing skills. Money well spent. George Morris was expensive, and of course on point, but the verbal abuse of one rider in our group was distracting (it was a long time go, when he was worse about that than he is now). I also enjoyed Scot King, and found his input to be useful.
Worst… I can’t really say. I find a rider/trainer can learn SOMETHING from everyone. I’ve had clinics I did not enjoy, or that were a waste of time and/or money, or didn’t go well, but there is usually SOMETHING that you can learn, if you try. I had one clinician who was working with figuring the exact fall of the feet at the canter, so that at some time in the future, a flying change could be asked for. I selected each diagonal across the ring, and did the flying change in both directions, as had already been acquired with this horse previous to the clinic without issue. Kind of deflated that clinician that day. But it was an outing for a green horse, and a different arena to ride in. Bernie Trauig was a nightmare for me, but even with that, I learned something valuable from him that remains with me 25 years later.