OK, I finally have a few minutes.
The
Scuba Diving with Scuba Fun Dive Center, Philipsburg St Maarten St Martin treated us very well. They have 3 boats, a zodiac, a mid-sized boat, and a cattle boat. We dove all 3. None of the boats were ever crowded, although the cattle boat looked full when they had the cruise ship group. That was the day that they sent 3 of us and a DM out on the zodiac and allowed us to drift dive. They do an excellent job of splitting up groups based on experience and air consumption. We never had more than 4 divers per DM and most dives had nearly as many DM's as divers. There were a couple of DM's that were new to St Maarten and learning the sites diving with us on several dives. The vis on all dives was about 80', not perfect but pretty damn good. All dives were at moderate depths 40'-80'. They also do afternoon dives but we were warned that is when they do discover scuba and checkout dives and weren't done on great sites and were shallow dives, so none of us went on one.
The Carib Cargo, was an interesting wreck dive, a fair amount of penetration if the DM thinks you'll be safe. The reefs were moderately healthy, definitely worth seeing. As for marine life, we saw a few reef sharks a couple of nurse sharks, several turtles, several spotted eels, a really cool bed of garden eels, and all of the typical Caribbean fish. None were overly abundant or huge but it was a nice variety.
Saba, once again, WOW. I wouldn't even think of diving it without a computer. Most of the sites were fairly deep at the beginning and they let you dive the limits of your computer if your air consumption allows it. My 3rd dive there, (the easy shallow dive) my computer logged 80' for 64 minutes, obviously we started deep and ended up shallow. The marine life was larger and the reefs are more healthy. We were diving with Saba Deep, they treated us like kings. Unless you insisted on doing it yourself, they did all of your gear setup, tank changes, and rinsed your gear when you were done.