Both last year and this year, Jackie and I enjoyed a meal at Guernica. Both times, we stuck with the tapas menu.
The sister restaurant is Bambu, further toward the Divi. We ate there last night, and all four of us agreed that it was the best meal we've had so far this trip. Not only was it good, but the portions were just the right size. None of us felt stuffed, and, as my brother-in-law would say, "A really smart person would know to quite right now." However, we talked ourselves into walking over to Unbelievable (ah, the illusion of having exercised!) for a couple of pieces of key lime pie, after which we all agreed that we had foundered ourselves.
Can't comment on the prices at Bambu, because it was my brother-in-law's night to pick up the tab... I do remember that, at least for a brief while, if you dine at Guernica and take a receipt for the bill to Bambu, you get a 10% reduction.