We took the bus for about $2.50 each (one way). Had to do a bus exchange at a stop, but tell the driver when you get on where you're headed, and they'll direct you. The buses are like mini-vans. The "stop" is at the end of the road, so you need to walk a quarter or half mile to get to the beach bar at the other end.
Our friends took a taxi. It cost them about $15 one way. We didn't notice taxis hanging around, but I'm sure being right next to the airport you could find one easily or walk over to the main road where the bus drops.
We met some people while we were there who were headed back to town, so they dropped us off at the dock (they were staying on the island, and leaving that day, so when they saw their plane land, that's when they knew they needed to go grab their things back in town). The beach bar is a great place to hang out. We sat at picnic tables, had drinks, and took pictures. (Have one picture posted: www.cmgoddard.com
and click on Cruises in top left - look at our S/S Norway cruise)
The one thing I caution: there is a drawbridge between where the cruise ships are and the airport (SXM). The drawbridge caters to the rich yachts. Apparently, when they all start coming back in during late afternoon, traffic can get backed up because the bridge is up so much. Don't want to miss your ship. I think we left about 3:00 when the last tender was at 5:00 just to be on the safe side. It was maybe a 15-minute drive.
But yes, definitely go! We loved it. I'm just a lowly math teacher and loved itl! It was totally amazing. Be sure to check various airline schedules on their websites of landing times at SXM. Try aa.com for flights SJU-SXM and MIA-SXM, Continental for flights Newark-SXM, and Air France for flights (nonstop!) from Paris (is that CDG??) to SXM. We understand most come in after lunch, so that left the morning for us to do some shopping and head over to Marigot for an early lunch at Le Bacardi (an open air little establishment with very yummy beverages!).