I've got a Bultaco 350 Alpina just like the one in the video.Nice old bike. Just picked up an 81 Montesa 349 Rathmel Replica (in rough shape) off a ranch in the middle of nowhere.
Trials riding is a very good way to develop extra riding skills, McGrath had a Gas Gas in his prime and David Knight started out in trials.
I've had many Spanish trialers over the years and they have been trouble free.The latest ultra light trialers may be fragile though.