I also dove with Ocean Explorers on a cruise stop. It turned out there on that day, a few crew members from the ship were also doing their checkout dives for an OW course with them.
- We had to pay for our own taxi there and back. I think it was $8 each? Downside: surly taxi driver. Plus side: shorter boat ride and diving on (I think) some of the nicer areas that aren't as accessible to the shops that leave out of Phillipsburg. After the dives, the shop called a taxi for us and we went to the restaurant across the street to eat lunch.
- They are a pretty well run op, right off the beach. Husband and wife team. Decent rental gear though I brought my own.
- The boats are not huge - no head, not much shade, a little awkward gearing up. Plus side - small groups. Downside - we got grouped with the OW students. However, it wasn't as though they were limiting our depth. As I read somewhere, around St. Maarten it's impossible to go deeper than 55 feet without a shovel.
All in all, I would say they run a good operation. Many years ago, I dove with Ocean Safaris and I much preferred Ocean Explorers. Just keep in mind that the diving has less vis, more current, and less fish/coral life than some other areas of the Caribbean. I read some suggestion that the French side is better but still not spectacular. If I could have, I would have taken the plane or ferry to Saba for the day and dived there.
Have a great trip!