I did my PADI open-water certification with Alex. This entailed two six-hour days, during which we did four dives, as well as classroom and confined-water instruction.
Throughout, Alex proved to be a skilled, observant instructor, capable of adapting his teaching methods to his students. I am a cerebral learner, while my classmate was more of a visual learner. Alex was able to tailor his teaching style to successfully impart the skills and knowledge necessary.
Alex is gregarious and funny, and he frequently cracks jokes. Nevertheless, it is clear that he takes what he does very seriously and makes sure that you understand and retain the skills and safety lessons you need.
Should I return to Oahu, I would not hesitate to dive with Alex and his staff again. In fact, I wouldn't even bother looking into other options.