There are probably more Mexican restaurants in Los Angeles than there are BMW 3-Series (otherwise known as the Bavarian cockroach), fake platinum blonds, dirty hipsters, Hollywood agents and out-of-work actors! I've counted at least three just walking to my local coffee shop, which is only several blocks from my apartment. They seem to slot into three categories: (i) the "cheap hole-in-the-wall", (ii) the "mid-priced sensible family establishment" and (iii) the "overpriced gringo trap" (note that I must be a gringo because, as I learned from the OC Weekly column, "Ask a Mexican", only gringos call other non-Mexicans gringos).
The cheap hole-in-the-wall is great for those times when you want super-authentic Mexican food but (a) have no money, (b) are drunk or (c) crave a jumbo serving of lard. It generally does not have a liquor license and may possibly have cockroaches. Places that come to mind are Chano's on Figueroa near USC (home to starving USC students and all motorcycle cops, who seem to park in the red-zone in front, because they can), Hola Cocina Mexicana in the strip mall on the corner of La Cienaga and Third Street and any place in Grand Central Market downtown.
The mid-priced sensible family establishment tends to also have fairly authentic Mexican food but may veer into Tex-Mex hell or even worse, New York style Mexican food, where they give you peas in your burrito (stay away from a New York burrito)!?! You go because (a) you do have some money and (b) you don’t really feel like dining with the roaches. It may attract a strong gringo quotient but it's not the rule unlike the overpriced gringo trap (see below). It may or may not have a liquor license, but if it does, the drinks are reasonably priced. Restaurants that fall into this category include El Coyote, El Compadre, La Barca (near USC) and Casa Escobar. I think El Cholo rides the line between sensible and gringo trap since the place is not too expensive but is usually teeming with gringos.
Then there is the overpriced gringo trap. It’s Mexican food tarted up and sold to gringos like me (except that I am an Indian gringo, they have those). Such gringos include white collar yuppie hipsters who think that dropping some cash to eat a lobster burrito infused with kumquat juice and rose petals is high times. It will suck you in to paying $25 for an entree and $15 for a margarita. There may be a Mariachi band that plays for you, un-requested of course, and then blackmails you into paying them $10 when they are done. The food may be decent but all-in you can't walk out of there without dropping at least $80-100 for a dinner for two. It may not even be owned or run by Mexicans. Go to Spanish Kitchen on La Cienaga or Frida on South Beverly Drive to watch the merry gringos dine.

Enter Lares. It doesn't serve too much lard, the drinks are reasonably priced, and the place is not gringo city USA (which I believe is Panama City, Florida). The fare includes the usual suspects: tacos, burritos and enchiladas, but also very authentic entrees like tongue, chicken or meat, all with various types of mole sauces, or shrimp wrapped in bacon and cooked in hot sauce. You can also get shredded pork or steak with cactus. It is dimly lit, but not too dimly lit, with comfortable booths and tables situated on two stories with lots of exposed wooden beams and wooden floors. Also, no roaches and you won't need to take out a second mortgage (or third for some people in this town) when the bill arrives or grab a bottle of pepto bismol when you get home. It's not in a particularly trendy part of town; located on Pico Blvd. just west of the 405 across from a McDonalds and near McCabe's Guitar Shop, which means you may actually find street parking. For the parallel parking impaired, Lares does have a valet. Lares is yet another Mexican restaurant in a town crammed full of them but given its reasonable prices and elegant decor it's no gringo trap or cheap hole-in-the-wall.
[Note that there are some Mexican establishments that do not slot neatly into my three category world. I understand that life is not black and white or in my world black, white and brown? There is the hybrid, which (a) may be trendy and full of gringos but actually serves good food and is inexpensive or (b) is not trendy, still full of gringos, inexpensive but with horrible food. Places in the former hybrid category include Malo (see previous review) and in the latter, Chipotle (uggh). Note also that if you ever willingly go to Chiptole, don't tell me because I will cut you out of my life.]
Lares, 2909 Pico Boulevard, Santa Monica, California.