We were on the Cayman Aggressor several years ago and it was a great trip. One of our best dive vacations ever. The ship, crew, food, and diving were all terrific. We had beautiful weather all week and did most of our dives off bloody bay wall. The reefs were gorgeous and the visibility was spectacular; we were there in late October.
We spent the following week on Grand Cayman and the weather quickly turned bad and stayed bad. We only went diving one day and it was raining, rough, and not great. We went out with Red Sail and they were a fine operation but the conditions were poor. After that day hardly anyone was going out because the seas were so rough. One day we saw the Aggressor moored on a site off GC and realized that they couldn't make the crossing and we felt lucky not to be on her.
Of course, the relative success of any dive trip is always strongly influenced by the weather; but an advantage of a liveaboard is that they are flexible and able to change itineraries to find the best options and take passengers to the best dives - if any are available. Land-based operations try to do that too, but their range is limited.
This flexibility has "saved" vacations for us a few times. We once were chased by bad weather around the sea of cortez on a liveaboard; the conditions were rougher than we would have liked but we still had a lot of great dives. When we got back to Cabo we found that no one had been able to go out during most of the week so we happy that we had been on the boat.
The same thing happened once in the Bahamas. We had registered for a liveaborad trip of the southern Bahamas but the Captain announced that we would stay in the northern region because it offered the best weather and dive conditions. We were disappointed but happy that we still had the chance to spend our vacation diving on beautiful tropical reefs.
Other advantages of a good-quality liveaboard is that they are all about great diving. They seem expensive but when you compare the costs per dive for your vacation (total costs for travel, accommodations, food, and diving divided by the number of dives) the liveaboard is usually much cheaper than a land-based vacation because you get so many dives - and often they are fantastic dives.
However, if the weather is bad and the diving is poor (or unavailable) then I would prefer to stay in a nice warm hotel with the chance to stay dry and enjoy some topside attractions. A diving vacation is always a gamble, whether on land or sea, we have learned to take our chances and try to make the best of every trip. Sometimes luck was with us and other times - not so much - both on land and sea!
One thing I forgot to mention about our trip on the Cayman Aggressor. Even though conditions were great I was really seasick during the deep-water crossing over to Little Cayman. I felt fine by the next day but I could have avoided that unpleasantness by flying over to LC (at extra air expense) and staying at a hotel. There are a lot of trade-offs, you just have to weigh the pros and cons, make your best decision, and keep your fingers crossed!
