My wife and I go there fairly regularly. It is an interesting, most times pretty good, South American restaurant. (By that I mean their menu offers a mix of Cuban, Ecudorian, Colombian, typical Mexican, etc cuisines.)
A touch pricey but not overly so, but they do have some really good dishes (our favorites are Mote Pillo con Lomo Assado (I butchered this I think..it is grilled pork loin served with hominy) and Camarones a la Diabla (shrimp...hot!). Both are good.
Appetizers are good too, though think starch. the Plato Sabor Latino (with fried plantains, yucca, etc) will keep you well starched. (and it huge, too much for 2, even 4)
Typically empty, most times just us, maybe another table. (It does get crowded, our understanding is that dining picks up later in the evening, though later than is practical for us) We have yet to encounter the mariachi.
Overall a pleasant and tasty experience. THey stock a few mexican import beers there as well (Modelo, Sol, etc)
Good place to enjoy a meal.
If you want to try another local hidden spot...two or three doors to the left is a little place called Sol De Peru. An authentic Peruvian. We've only tried it once so far, but had a very pleasant experience there recently. The owner is very amiable and will discuss the menu at length with you should you desire. Menu - think basic grilled meats, starches, heavo on the potato. (Try the Pisco if you go - Peruvian blue corn drink.)
I was there last year. The food was good but a little pricey, especially for the neighborhood. We were there for dinner on the weekend and it wasn't too crowded - there was a mariachi-type guitar player there which would have been nice if there were more people in the restaurant. As it was, it was so uncrowded he was really playing only to us for our entire dining experience which was VERY uncomfortable...my favorite Mexican for taste and price is BYO Taqueria Morleon in Kennett Square. Quite a haul but worth the trip.