This whole-in-the-wall type taco and burrito establishment really makes great tasting food. I recently tried a plate of three different tacos which was terrific. The three tacos, chicken, al pastor and carne asada were each really excellent. The chicken was moist and flavorful. The al pastor was smoky and had a great peppery flavor and the carne asada was simple and juicy.
Fast Taco keeps a great salsa bar which may be the cleanest salsa bar in all of Los Angeles. They also make great plates like the Carna Asada plate I enjoyed the other day.
Try it when you're in the area.