There are usually more divers from the Road Town location, however and sometimes the number on a boat is substantial. The dive package includes three boat dives per day. Shore diving is not really available. Night dives are available but extra. Virtually all dives sites have significant fish and coral populations.
Some dive sites have greater chance of large pelagics.
However this was on the Atlantic side of Tortola which is rarely dived. Angels include Queen, Gray, French, Rock Beauties. Many varieties of Parrotfish, tangs, damsels, chromis, etc. The Apple Restaurant had good conch and fish, Pussers had good deli food. Night life on Tortola is a bit sparse.