CSS has a very basic dive boat (think the glass bottom boat at CTI) because of the reef they can't get a big dive boat at the resort. We dove many of the same places on the same dives as the CTI group. We would always be their first then see their boat when we surfaces - not sure if that was coordinated or not. Leon is the main dive leader - he was a little slow to warm up but I thought we had a good rapor after a week of diving.
As experienced divers (15 years) my wife and I were somewhat disappointed with the diving at CSS, but realized going in that Jamaica is not a dive destination. We did have one excellent dive, the HMS Catherine, an old mine sweeper that was loaded with football helmet sized brain coral and situated next to some very good 'swim throughs'.
That said, I would go back to CSS in a heartbeat.
(Leave your gear home, theirs is in good shape and you won't have the hassel of carrying yours through the airport.)