Everything was great.  Service was quick, attentive, and friendly, and not intrusive.  Blood orange mojito was incredible and very refreshing.  The plain mojito was not great, either over-muddled or using old mint, as it was very bitter and the mint was black in places.  The tortilla espanola was the least favorite dish.  It was okay, but the potatoes were underseasoned and undercooked and the dish as a whole was nothing special.  On the other hand, the patatas bravas, the mac 'n' cheese, the steak and mushroom skewers, stuffed peppers, artichoke toast, fried calamari, were all to die for.  I believe we had one other dish as well.  Stuffed peppers were my personal favorite this trip.  Perfect balance of creamy and flavorful, sweet and spicy.  Textures and flavors all went quite well together.  Also, the chocolate tres leches cake was one of the best desserts I have ever had, and I'm not even a chocolate person.  Texture was great, and the bitter cocoa flavor of the chocolate sponge cake balanced the sweetness of the milks.  Firefly is definitely a winner.