Glad you enjoyed your trip...what set Salt Cay apart from the rest as far as being "phenomenal"?
Salt Cay has little to no dive pressure on it. You can tell by the condition of the reef, that very few people dive the site. The reef was very healthy, and the wall was very sharp there. Dropping off as a sharp cliff, rather than a softer slope like French Cay.
The top of the reef itself was only 30-40 feet deep, and the wall... well the wall just goes.
The wall has lots to see on it including some vase sponges, and in the deeper portions some black coral, and the shallows had an incredible amount of macro life as well.
What set this place apart was the shallow section of reef, and the volume of small critters, and more brittle (fragile) corals, that are often not seen. This included staghorn and some elkhorn coral. Additionally, the color and variety of the soft corals and sponges made this site a real treat.
Here's a few pics... They're compressed to fit quicker on the gallery...
Here's a diver who is at about 25 Feet, with the reef below him
This is looking up the wall
And some Staghorn Coral