Pretty solid food in the mass of mediocrity that is Oakland.
Most of the sandwiches are tasty. The pressed bread is crisp yet remains soft on the inside, which accents all the sandwiches' components. Their Cuban is delicious, they don't skimp on the meat at this spot. Try anything that includes their Island Sauce. I usually hate mayonnaise, but Black Bean's Island Sauce converted me into a believer.
Excellent sides such as black beans and rice, empanadas, island fries, and fried plantains round out any good meal here. The guava and cheese empanadas are an interesting dessert choice that I crave frequently. The big plates of food (Mojo Grilled Chicken, Arroz con Pollo, etc) are alright, though not nearly as good as the sandwiches.
Prices are reasonable, around $7-8 gets you a huge sandwich or big plate of food, another $1-2 if you want a side dish such as black beans and rice or an empanada. Service is pretty quick too for made to order food.
In short, a good spot to get a filling, tasty sandwich or some Cuban side dishes. I've become a regular since it opened, and you will too.