Re: La Guerite, will you be going to lunch at the beach restaurant or dinner at the Gustavia locale? Both are quite expensive, but I like the restaurant at the beach. The food is very good . . . the setting very pretty . . . and excellent service, in my experience. The Gustavia venue, on the other hand, is -- I believe -- even more expensive. It also seems to have had, when I've been there, a very lax attitude toward smoking . . . and the decibel level, high in any event, is ear-splitting after about 9 PM.
Lots written here about La Casina and Nyama (latter is a great favorite for me) . . . some commentary about Sella (comments have dissuaded me, so far, from going there . . . though I'll have to try it sometime to form my own opinion).
L'Esprit . . . best food on the island right now, with sophistication and subtlety in ambiance that is as close to "old St. Barths" as one finds in SBH fine dining. Service can be slow (which fits my dining style just fine!). Wines are very reasonably priced.
Ti Corail . . . a great luncheon hit. Charming, "toes in the sand," old St. Barths territory . . . with an excellent, very limited menu. Lovely beach setting. Parking is difficult. Reservations required.
Tamarin . . . I think that Ellen (elgreaux) said it best -- go for appetizers & cocktails in the garden. Gracious and stunning setting. Dinner in the traditional format -- i.e., under the roof (the "Colonial garden house") or at a table in the nearby garden of palm trees and lush vegetation -- can be very nice and very good. Every time I go there, however, I leave with a lingering feeling that the "package" is "corporate" . . . almost Disney-esque.
L'Isola . . . I think that Cass has "nailed it" in his above commentary. Priced to exclude and very clubby. Nonetheless, if one gets a seat there (a difficult order!), the food is simply and very well prepared . . . with fresh ingredients, in a traditional Roman style. The candlelit setting is lovely, and the vibe is lively (if you're noise-sensitive, request seating in the "back room".)