We and our villa Guests have done both recently.
It depends on your group. More formal/button-down? Then LeGaic for sure. White tablecloths, outstanding views, nice ambiance, service and fare.
Manapany: remodeled, European feel, few Americans when we were there mid-Dec., this may change in high season. Waves crashing on the beach nearby... Three separate courses--30E, an excellent value. More casual, bring your suit, laze/swim in the deep, gorgeous pool (good advice from buddy JimmyD) or plage walk afterward, take your drinks out to the deck overlooking the ocean. Not a bad way to spend a SB afternoon...
Note that both are almost like two meals so in our case we know not to plan another large one that evening.