I can only speak for the Belair Beach Hotel on SXM. My parents stayed at the Belair this spring and loved it. There is a great restaurant/bar on site. Two or three nights they have live music, and Friday night you can reserve a romantic sunset dinner on the Beach. My parents said they set up your table on the sand beach and serve you your meal as the sun sets and the waves roll in and out. In fact my parents said the restaurant had much better food than the places at the Divi next door and better than most places they ate on the Island.
They said the Belair was an older resort, but well maintained, and every unit is ocean front with private balconies. They watched cruise ships sail in and out of Phillipsburg daily from the balcony. They said the water is that turquoise blue that the caribbean is famous for, and drinking coffee every morning on the balcony was one of their favorite parts of the trip. Many of the paid snorkeling trips bring tourists to the jetties over by the Divi because it is some of the best snorkeling on the island. My Dad rented a mask and fins and simply walked over there and snorkeled daily.
My parents went all over the Island and said they liked it better than any Island they have ever visited including Hawaii. One half of the island is French and the other half is Dutch. The Fench side is the Euro whch has a bad exchange rate, but the Dutch side exchanges one for one which makes prices there reasonable. My father said driving from the airport to the Belair he knew that he was going to love this island. Phillipsburg SXM was voted the 3rd most popular destination in the world for 2008, and number one in the caribbean on trip advisors annual list.
http://cdn.tripadvisor.com/pdfs/tca/TCDestinationsAwards2008.pdf .
They said the island has 20 something different beaches which have everything from calm water to decent waves, white soft sand to rocky beaches, shallow wading water to deep swimming locations, and bikini clad sunbathers to nude beaches. Orient beach (half clothed, half clothing optional) is usually rated one of the top 20 beaches in the world. Maho beach has the closest beach to an airport landing strip of any in the world. My father went to the Sunset Bar right on that beach and said they have the landing/takeoff times of the jumbo jets listed on a chalk board. When a big jet is coming people walk down to the beach and watch the jet fly directly ovrhead on it's way to landing. Go to youtube and search St Maarten airport videos to see it. It has to be an unreal experience.
I have not been to SXM yet, but after my parents great reviews and beautiful pictures it is a trip I will take in 2010, and I will try to stay in the Belair Beach Hotel (I would go to SXM in 2009 but I have already booked Aruba). I am sure you can't make a bad choice with any you listed, but my parents think SXM is the best place they have ever been for the food, the beaches, and the shopping. Their only complaint was the traffic which they said is horrible.