OD was recommended by our local dive shop and we were not disappointed. We did a a dive and lodging package, staying at the Marina Del Mar and this is the way to go. Our room was steps from the boat, which allowed us to go back to our room between morning and afternoon trips. The rooms at the marina were basic and a bit dated, but perfect for our purposes. The people at OD were all fantastic -- very helpful and enthusiastic. We did 8 dives, including a 2 dive specialty with Adrian, who was very thorough and patient. We hope to do more training with him in the future. The office staff -- Connie, Louis and Joe -- were all very helpful and top-notch, as were DMs Marcus and Mike. Cap'n Jim was very safety conscious. Both boats are loaded with safety equipment. Only two small nits. One is that one boat carries aluminum tanks and the other steel, so switching back and forth makes buoancy interesting. Also, one of the boats has a bungy system for securing the tanks (actually very common, but I hate them) and we saw a number of tanks topple because people are not securing them properly. I'd hate to lose a toe to this and would prefer to see an upgraded system next time.
In sum, I highly recommend OD -- I won't go anywhere else in Key Largo. I'm already dreaming of next time.