Cons: Almost as noisy and crowded as gridlock in NYC
This would be recommended without reservation if the owners could fall back down to earth and run a restaurant along normal lines -- without bizarr-o amateur-"artist"-cafe-style-decor, without a 90-decibel noise level, with even marginally reliable service, with...argh.
Assuming you go at a busy time (say, 6pm on a Tuesday), you're guaranteed a wait, and the odds are decent that you won't actually have anywhere to stand. I realize this is Los Angeles (Santa Monica, really, but close enough), but there's only so much of that one can take. Come on, stop writing your silly cookbooks and put in some more chairs!
That rant aside, everything else is swell and somehow worth all the hassle. Their scratch drinks are potent and tasty enough to leave you sufficiently buzzed to ignore the noise. (A large part of the restaurant is taken up by a bar, and I will probably go there one night for the sole purpose of emptying my wallet on the well-mixed drinks.)
Cuisine runs the gamut from predictable Southern California (chiles rellenos) to strange dishes whose names evaporate from my mind after I stop looking at the menu. They are all done in fine style, which somewhat rationalizes the wait and hype of this place, and makes up for all the hassles of your waiter serving fifty other people. Don't go in with your mind set on something pedestrian like cheese enchiladas; the Border Grill has a lot of trouble producing that which can be had elsewhere.
Between the drinks and the large number of dishes you're likely to order, this is a bit of a costly jaunt for what it is: expect a tinge of bitterness at having to whip out the plastic even though all you thought you had was a quesadilla and a daiquiri. There are other pretentiousness issues, most notably in the form of pseudo-exotic ingredients, but I'll let that pass: despite all its shortcomings, the Border Grill is well worth the calorie and cost expenditures.