Many nights I feasted on fresh lobster and flounder that cannot be matched anywhere. I also dove for fresh clams in the waters of RI without disappointment. The diving experience is something you take with you anywhere. Whether fresh water diving in lakes, diving the Great Barrier Reef in Australia, the Florida Keys or depths offshore Hawaii, PADI Open Water certification gets you into the water wherever you may go. Snorkeling may be fine for some people but if you really want to experience the natural beauty of Mother Ocean, you need to spend some time wrapped up within her.
Differences are what make the world an interesting place.
Good instructors and no-nonsense training. The best time to learn emergency procedures IS NOT when you are 60 feet under the water. PADI knows this and trains accordingly. My PADI instruction consisted of classroom work, pool exercises, and open water dives in the East China Sea. I was stationed in Okinawa and decided that living on an island within walking distance of the ocean was a good excuse to learn diving.