La Estacion was our favorite night out in Fajardo: delicious, authentic, fun, reasonably priced, and comparatively vegetarian-friendly (though I hope they add a few more single-sized vegetarian dishes).
La Estacion is similar to Trailer Park in NYC, but with far better food. The decor is kitch and cozy. Diners were dressed in casual and clubbing attire alike, so anything goes.
The cocktails... wow! My boyfriend had a Mojito and I a Cocotazo with rum. Both were fresh, dynamic, and pretty strong. My boyfriend had the catch of the day for 1, which was far too large a portion for him but he said it was one of the best fish dishes he's ever had. I'm a vegetarian, and I enjoyed plain mofongo and a papaya salad, which was a lot for one person but delicious and refreshing.
The service was super-friendly: attentive but not overbearing. We highly recommend La Estacion!