I was there about 15 years ago and don't remember where I stayed, but all I can say is it's going to be hard to go wrong with pretty much any hotel or restaurant on the island.
If you've been to islands in the Caribbean before, you know that outside the resort itself they are almost all unanimously run down, with some being outright dangerous. Service and the locals are also usually slow and/or unfriendly. St-Barths is basically the exception to this rule.. It's run by French elites, not the "locals", and hence feels more like a town along the cote-d'azure than the Caribbean. That means restaurants are run by French people, for French people, so there really is no shitty food. The island itself is a magnet for movie stars and rich French people, and though I don't doubt that there are shitty hotels somewhere, for the most part the island is immaculate, modern, and caters to expensive tastes.. Expect to probably put on 5lbs as the standard French breakfast there includes butter croissants, chocolate bread, and tons of jams/marmalades..
P.S: Have fun doing the dive bomb mission to the island's landing strip in a puddle jumper. Landing at that airport is freaking scary.
P.P.S: Enjoy all the free titty viewing on the beach.. Once you do a French run island it's hard to go back to American/British ones.