I was in SOMA and stumbled upon this truck, doing a pretty good business. I was there for maybe 5 minutes and they served 12 people around 1:30. Around noon I have to guess they do quite well. I didn't have time to eat more then 2 tacos soI had the carnitas and al pastor. $1.50 each, small size (referred to as taquitos on the menu). Burritos were $5.
The carnitas was very good, moist with good flavor. The al pastor wasn't to my liking -- the texture was almost ground meat with too much sauce...might work in a burrito but that's a guess and a preference call. The other items were lengua, carne asada, pollo asada. Was interested in the lengua and pollo but couldn't justify it.
I don't know the go to items but I'd go there for the carnitas on regular/weekly basis if I worked near by. The side of the truck stated South SF, so I'm guessing it's related to the restaurant there.
Sorry no link...it's on the NW corner in the commercial parking lot. I'm guessing they pay them.
Los Compadres Taco Truck
50 Tehama St, San Francisco, CA