Puerto was a great town, I loved it - very laid-back, lots of backpackers, quite inexpensive. Surfing is a big tourist draw, which contributes to this atmosphere. I've done quite a bit of traveling in Mexico, and I think it's been my favourite destination so far. The dive shop was Puerto Dive Centre (
http://www.scuba-diving-mexico.com/) and our instructor was a truly terrific guy named Jeff. Can't say enough about him - he made my husband, who was a tad nervous, feel totally at ease. He’s also a great underwater photographer and took some wonderful shots which he’ll burn to a CD for you (for a small fee, of course!). But I don't know how long he'll be working there.
I obviously don't have much of a basis for comparison for the diving. Having done lots of snorkeling and one 'Welcome to Diving' experience in the Caribbean, I can say that it's obviously very different on the Pacific. There were two different spots they took us (I did eight dives while there). One, called Punta Colorada, had beautiful formations and lots of big schools – I picked my user name because of a wonderful, big school of jacks that circled us on my first dive as a certified diver – totally thrilling for a newbie like me. We also saw some great stuff from the boat, like a school of flying mantas (had never seen anything like that before!) And of course, there’s tons of sea turtles.
All and all, I would absolutely recommend a trip to Puerto.