I have done a number of live aboards (Bahamas, Turks & Caicos, Belize, Fiji, Socorro and Isla Guadelupe) and in my humble opinion, it is the best way to do a dive trip.
A little background. I typically only get one dive trip per year (some years are better than others), so I like to maximize my bottom time. I would have to say that for the most part, my experiences on live aboards differ significantly from those mentioned by VR78.
I have found that the food on every live aboard that I have been on has been outstanding and extremely plentiful. The crew realizes that if you are doing 4-5 dives a day, that you will be burning a lot of calories so they will do their part in providing you the opportunity to replenish those calories. They will typically do their best to ensure that they are serving what you want. (They may stretch your comfort zone somewhat though.)
Cabins vary dramatically from boat to boat. I have been on one live aboard that only one person could stand up at a time because the cabin was so small, and I have been on others where the cabin is the size of a small hotel room.
As for way the diving is managed, that tends to vary from boat to boat. The Belize Aggressor would give a comprehensive dive brief when we got to the site and then announce that "The pool is open". The only guided dive was the Great Blue Hole. The Aquacat (in the Bahamas) and the Turks & Caicos Explorer would put a DM in the water with you on every dive, but you were never under any obligation to follow the boat's DM, and you could do your own thing. On the Drift Dives from the Aquacat, however, they did want the group to stay together. On both the Solmar V (in Socorro Islands) and the Nai'a (in Fiji) the diving was from Zodiacs, and sometimes the DM went in the water and sometimes they didn't. I have never found that the group was limited to the local air hog's (often me unfortunately) bottom time. Nor were they hamstrung by anyone taking pictures (again often me). Depending on how far the boat is from the closest Hyperbaric Chamber, the boat may place restrictions on depth. The Solmar V checked everyone's computer when they came on board to ensure that you did not go deeper than 100 feet. If you did, you sat out for 24 hours.
Diving is what live aboards are all about and the crew will bend over backwards to ensure that you get the most out of each dive and out of the trip as a whole. Your tanks will usually be hooked up to the compressor as soon as you get out of your BCD and if they find out that you (like me) are a little hard on air, then they will try to ensure that you have a very full tank. On many live aboards, a typical day will be some variation of:
- Get up grab a coffee and/or juice
- Dive site briefing
- 1st dive.
- Boat moves to a new dive site while you have breakfast
- Dive site briefing
- 2nd dive
- Boat moves to a new site while you have lunch (and maybe a nap)
- Dive site briefing
- 3rd dive
- boat moves to a new site while you have a snack
- Dive site briefing
- 4th dive
- Supper
- 5th dive (night dive at the same dive site where you did the last dive of the afternoon)
- Boat relocates over night.
I hope that helps. Have a great trip.