Izalco does pupusas like they are supposed to be done. In their bean and cheese variety ($5.50 for 3), the discs are stuffed full and oozing their insides at every bite.
Better than your average Roosevelt Avenue Latin restaurant, Izalco's walls are adorned with photos, trinkets, and small handicrafts. There is even a deer head. The place is always filled with Central Americans. Try the elote tamales and enchiladas, both are different than their Mexican counterparts. I've had better salpicon.