Barrachina's is a good place to go for local Puerto Rican fare. Also, it is the birthplace of the Pina Colada. With this in mind, there can be a lot of tourists there, especially during the day. Go for a later dinner, and you may well be one of only a few occupied tables. The entree was about $15 to $18 while a pina colada was about $6. And let me tell you, I don't like Pina Coladas, but I got one since this place is "famous"-it was WONDERFUL.
Try the Chicken Mofongo! And if you're lucky, Carlos will be your waiter!