We were in SXM between Christmas and New Years in 2014. If you want to dine at any of the better restaurants in Grand Case, you will need reservations, yes. And if you have a particular place that you HAVE to go, suggest reservations before you leave home. We wanted to go to Temptation, which is one of the hardest reservations, probably, and we gave Dino almost a 10 day window around that timeframe and he was able to shoehorn us in at 6 PM one night, only because we were just two people.
The other issue with travelling around the holidays is how much 'fun' air travel is. I really enjoyed going then, but probably wouldn't be in a big hurry to go back again at that time period.
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