I had an absolutely wonderful experience with DSD at the resort in Puerto Vallarta. I was with my my 9 year old son (I know, too young, but he did as good or better then most adults). We had a class session (discussion then PADI video), then pool exercise (mask drills, air sharing, VERY BASIC buoyancy, things like this). Then it was OW. I was a bit heavy at the begging, instructor took some lead off me, then I turned maybe pound or two too light at the end. Surfaced with like 200psi in the Al80 (I let instructor know at like 600, he hand signed to continue, I had a lot of extra gas right next to me in my son's tank, so I didn't worry too much. Anyway, about an year later we had OW cards in the mail (Jr. OW for my son, obviously). OW was super easy, we did most of the skills in our DSD. We just blew through the course with no issues.