Used to do an annual thing with them and they're great if you don't need fancy frills. The routine is up at approx 8:00 for a morning dive. After the dive they'll motor to the next site. Then a mid-day dive. Then more motoring(as someone else observed, there's not much sailing). Usually there's an afternoon dive. Once or twice during the trip, there'll be a night dive. Depending on your stamina you can get 14-18 dives per trip.
Usually we would go to Bimini and dive that area. However, weather is the deciding factor and we have gone to Andros and other points in the Bahamas. Although I never went, I understand that they also sometimes go to the Tortugas.
They've got both single and double bunks. The max number is 20-22 people plus a crew of 4-5. The meals were simple but always good. Big plus...unlimited beer on tap every day after the diving is over.
It's more fun if you go with people you know but not mandatory. The DM will help you find a buddy if you're alone. Besides, on a 65 ft boat, you get to know everyone pretty quickly.
I always went in the summer. Never needed any type of thermal protection. Have heard from folks that went in the winter that you get pretty chilled after that 3rd dive. Also, staying topside in the winter isn't always an option like it is in the summer.
I'd highly recommend them to anyone diving on a budget or anyone who likes the close-to-the-water boating experience. It ain't no luxury cruise but it's a lot of fun.