Proper American style food (for the uninformed Europeans, this is not just any burger joint or…read morelarge-piles-of-food place), bringing out the best in American cuisine. This place would compete superbly in SF or NYC any day.
Burgers. The best. Period. I don't have burgers this tasty and well-balanced anywhere in California. Knowing the owner here since the opening a few years ago, the meat is double ground daily and cooked to order; I recommend medium-rare or a bit less ("a punto" or "poco menos de punto" in Spanish). For burger connoisseurs, I can attest to the bun's quality and pairing with the burger. The Liberty Burger is classic, with cheese and bacon plus freshies, but any of the rotating inventions (the Frenchie, the Alpine) are perfect for adventurous dining nights. Burgers don't come with fries, but you don't need em.
The LK also has one of the best selections of beer, from small brewers of many countries.
TIP: make a reservation, you absolutely need it. You can do it through a Facebook message on their FB page.
Extra TIP: if you come right after opening, you may be able to get bar seating for 2 or 3.
Besides burgers, anything else I've had was either excellent or at least way above average (using American American food standards).
Service is fantastic. All the good parts of American attentive service without being overbearing.