This place is pretty dang good. I can't say I have had much but I come here for the pupusas.
I usually come here with big groups, the service hasn't been the fastest but that could be because of the size of group I have been with. If you ask for something they will usually get it to you pretty quick though.
They give you free chips in some tomato based sauce with cheese on top like Jadira said. If you want more just ask and they will hook you up.
The pupusas are flavorful and super cheap. Most of them are only a $1.50. Can't really beat that. Well you could but they are worth the buck fifty.