Hi Ray,
Having just finished the trip week before last , I think I'm qualified to answer this. First, go with an open mind to allowing the Captain to pick the itinerary. They will do whatever is in your best interests, based on their long experience, to make your vacation the best and that includes taking you to Little Cayman and Brac when the weather co-operates. Captain Sam is a wise skipper and he and his crew do their utmost to please everyone but crossings are rough for some so he'll wait till an opportune time for those that have more problems with motion.
That said, we dove all those sites and Little Cayman was most excellent! The dive platform is comfortable and easy to exit and get back on with help and supervision all the time. One thing I'd suggest is to dive with the divemasters aboard. They are all instructor rated and know the sights and will find the creatures for you. They also know the routes to maximize your dives to see more and at the right depths. We had Denise and Shauna as the regular divemasters, along with Tom who generally runs the office in Cayman along, and they could not have been more helpful. BTW, don't try to grab a hot towel to dry off. This will always be done for you, along with a relaxing neck massage.
Take extra large pants and shirts, as Yanis the cook, will provide you with more calories than you think you can handle. Food is always good, hot and plentiful! Several nights you will be treated like royalty and served more formally with wine and a more elaborate meal if thre is no night dive, such as a crossing night.
Cabins are all generally the same but the guests in the front cabin complained about being woken up earlier with the cleaning of the deck above. This cabin is generally nicer, has maybe a few more feet of walking room, and called the "Honeymoon Suite". Don't take much along as their is adequate space for storage but not much. Plenty of room for your dive equipment on the deck, but as no wet stuff comes down, all you need are a few clothes and toileteries. Take several suits as they get wet often. I did 21 dives and this is with an afternoon off!
Hope this answers some questions but if you want more clarification, let me know. you'll have a blast with Captain Sam and Crew. They will tell you in the beginning how dedicated to making this a greta trip and then go about showing you how special you are to them. While I can't comment on the other operators, Cayman Agressor is a great dive vacation!
Frank