(You posed this in another Bay Islands Forum thread as well)
I have a unique perspective on your exact question.
I started diving Cayman in the early 70's, and last stayed at Sunset House in 1990 or so. Having seen Cayman in the 1970's, the reefs were unfortunately a victim of island's success. We came back after that and did a liveabaord with marginally better results.
Cayman is known for "gin clear water" which means that the ocean gently sweeps by and carries off siltation, and even more important... carries no siltation to Cayman from neighboring developing islands. Even so, the reef has degraded to such an extent that the dive sites that were wildly popular in the 70's and even into the eighties... they are essentially moonscapes.
The shore dive off of Sunset House was nothing short of spectacular in the 1970's. This is the resort (and next door) that featured postcards of the bikini-clad hottie hugging the big green Eel, it had the huge Baracuda named Snaggletooth and a Grouper the size of a 15 cubic foot refrigerator. And In the 80's it looked fairly bleak. Today it is lunar.
Sunset House still maintains some of the feel of a "dive resort", some of which is attributable to it's physical plant, some because of the kind of people it does attract because of it's marketing.
Roatan is in fast forward development. We started visiting in the 70's there as well, and even then it was apparent that we had entered new territory for diving. There isn't as much water exchange. On the North side, there is a bit more, but the North is dark and deep- not so much to look at, but you ask about the South side, where the water exchange is slower, but the growth is shallow, lush and Sunlit.
Because of this development, the localized reef structure is beginning to show a downward slide. I believe that it still is the best Caribbean reef structure which is reasonably accessible to travelers, but it isn't like it was "back when". In "Cayman Years", I would put Roatan's unique and delicate South shore at about 1981 right now.
You can get the feel of a dive resort (and I use that term specifically) with a trip to CoCoView. It was built with one path in mind and the course has been maintained even after almost 30 years of operation. In terms of shore diving, it offers the single best access of any resort in Roatan.
If you want to log dives, you'll do better at CoCoView than SH, but that is an easy statement to say about any resort... CCV let's you dive a lot- I usually get 27 dives in a week- and I am old and beat up. (This is what happens when you start diving these places in the 1970's)
Roatan restaurants are a ways away from CoCoView, and some folks find great diversion in them. They are, by a Caribbean standard, pretty good. Would they survive in Alabama? No way.
Cayman restaurants can be spectacular. Just down the street from Sunset House used to be the fabulous Chef Tel's Grand Old House. What an experience... with a serious cost, but again- well worth it. Unfortunately, you can't spit on GC for less than $25. It is the Aspen of the Caribbean, much as Roatan is the Telluride (of 25 years ago).
Roatan has way more sand flies.
As an island develops, things change, and never for the better. I would go see Roatan, and especially this unique South side niche reef environment, before it ages any more... and it will.
Then you, as I reminisce about Cayman, you will be able to say, "Roatan? I remember when...."
