I was going to reply earlier, but since I've only dived Cayos Cachinos in the BI, I thought I'd let someone else take your question. Since no one has stepped up, I can offer a review of CC which is part of the Aggressor itenerary, IIRC.
Five of us dived from the SeaToye (a 56' sailboat) in March several years ago. We encountered a ferocious wind storm for the first two days at Roatan. We made two dives near Cow/Little Cow Islands which were totally forgettable due to low vis from the storm.
Once the winds dropped below gale force, the capt moved the boat to CC for the remainder of the trip. Diving was extremely easy, the bow of the boat was in 20' and the stern in 110' of water. Although we saw very few larger fish, there were nice sponges, corals, and macro life. A decent variety and number of tropical reef fish, a few eels, and octopus were also seen. Vis was consistently 75' or better and temps in the mid-80s.
Unfortunately, the weather never cooperated to allow us to get to some nearby seamounts which reportedly had congregations of larger life. We did visit a Garifuna fishing village which was pretty interesting.
Although I can't describe the diving as high-voltage, it was fun and relaxing. The Aggressor boat should give you a much broader view of the BI.