Tried the much ballyhooed truck at Harrison and 19th last night. It succeeds at those basic elements where most SF taquerias fail: small, hot corn tortillas with a few bites of meat, cilantro and onions, topped with tomatillo sauce, and fresh squeezed lime juice. The result is quite satisfying, if not spectacular. Although the search will go on, these will satisfy cravings and are the best so far in SF.
Carne Asada: the meat itself was fairly bland, but was sufficient as a base for the other flavors. It wasn't really browned/seared enough to bring out it's own flavors. Same went for the grilled chicken.
Carnitas: a bit tough, but I'll give it another chance next time.
Al Pastor: I don't like this style of smoky-flavored, starchy-sauced al pastor. I prefer more of the meat flavor to come through with brighter, savory flavors from the sauce.
Lengua: very tender, and nice light flavor on its own, but the subtleties got lost among the stronger ingredients. Still good overall.
Tortillas: I think this is why I like the truck better. The tortillas were hot and fresh and there is something special about the way that lime juice brings out the corn flavors of a good tortilla.
Salsas: I loved the green tomatillo sauce. Nice bright, fresh flavors that accented the tacos well. The red/hot sauce was smoky in the same way as the al pastor sauce and didn't have much bite.
Extras: Do not, as I did, save the carrots for a refreshing end to your meal. They live with the jalapenos in the big container and have stolen all the capsaicin. Very good and, after a delay, very spicy. Without food or drink to accompany, you will see through time Lisa Simpson-style.
To those who hesitate going to a truck, the two guys inside were quite friendly and spent every spare moment polishing the surfaces to a high sheen.
For reference, I have tried these places, but not liked them enough to want to go back. I will return to the Truck.
Taqueria Cancun (Berkeley)