Of the 12 or so certification courses I have completed, Deco Procedures and Advanced Nitrox were the best courses. My instructor was/is a practicing deep technical diver with over 8000 dives and even the DM for my courses was a deep technical diver with over 2000 dives. Deep is relative to the diver of course, these guys had done the Doria, lot's of dives on the U869, as well as other 300' cold water dives on trimix rebreathers of course. I wanted to learn from instructors who go to deep, dark, scary places.
Very well said!!!!