There are two boats very dear to my heart.
One is the Peace, in the Channel Islands off Southern California. The crew there works tirelessly for the divers. Safety is the highest priority. They don't complain about handing up and down scooters and cameras for 20 people for three days straight, and they get the tanks refilled immediately, and still have energy to dress up in costumes and go along with the "theme nights" our group comes up with. And the cook is utterly astonishing.
The other is the MV Tala in the Red Sea. We've done two trips on her. The theme of the trips has been extracting every last, exquisite drop of fun that can possibly be had from a week or ten days of diving. Whether it's beautiful, sunlit reef dives, or monkeying around on scooters, or draping oneself with a ridiculous amount of equipment to go see what's "down there", they make it happen. I love the flexibility of being able to do a technical dive one day, and monkey dive with scooters the next, and the fact that guides are optional and not prescriptive, but truly "guides". The use of the big screen TV and the 3D animations for the dive briefings is awesome. You really UNDERSTAND a wreck you are going to dive from that boat. I guess it's really the flexibility and the personal service that is most impressive.