I certified my Senior year in College. It looked like fun. The shop that taught the class was PADI. So I'm PADI OW & AOW. I'm NAUI Rescue. I'll probably do PADI DM 'cause that's the shop I deal with. It is the shop that taught the University course. It turns out they are the oldest shop in the area (Reno, NV) and stay consistant. That I like.