As a former employee of the LES Tenement Museum, I have a special place in my heart for Castillo's (as we always called it). This place is definitely a local spot that no one talks about. It's not fancy and looks like any other greasy spoon. Do not be deterred by your surroundings or the fact that it's not a "trendy" eatery. Go during lunch, have one of the lunch specials, and leave full and happy.
I went back to Castillo's on Friday with some friends and it has not changed at all. I ordered my personal favorite for lunch - chicken (leg & thigh) with black beans and yellow rice. It tasted exactly the same - a good thing! - and, as usual, it was too much for me to finish. We also got an order of tostones for the table which is served with some kind of garlic on the side.
Do not go to this place if you are looking for great service. They are pretty slow and inattentive. However, the food is still worth it in my opinion if you are looking for inexpensive and traditional Dominican/Cuban food.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.