Plata Grande certainly isn't your run-of-the-mill Mexican restaurant. For one thing, it's big, with four separate dining rooms, a bustling business and lots of staff. It's unusually handsome, too, with ceramic tile flooring, a fountain, plants and Mexican artifacts. Even the menu is a knockout, beautifully colored and illustrated.

How's the food? If you're used to most Washington-area Mexican restaurants, you'll find it very good. But if your expectations have been lifted too high by the beauty of the surroundings and the hyperbole on the menu, you may be in for a bit of a letdown. We found mainly adequate dishes, with a few delights and a few bummers. (Note that the service seems better on weekdays, when things are less hectic.)

One of those delights -- perhaps the most satisfying dish in the house, and certainly the most fun to eat -- is fajitas , available in both appetizer and entree portions. Strips of marinated beef or chicken are served sizzling on a skillet with a mound of vegetables, a basket of flour tortillas and a piquant salad. If you've eaten moo shi pork, you know the next step: roll your own. It's delicious, and a nice way to share a platter of food among a group of people.

The other appetizers don't seem as successful. The quesadillas were soggy, the similar roscas were sitting in a puddle of oil on the plate, the chili was ordinary, and the ceviche, although tasty, didn't contain much seafood. The complimentary tortilla chips, made in house, are unusually good, as is the delightful Mexican cornbread and the flawless Valencia rice.

There are two kinds of entrees here: standard Mexican fare (tacos, tamales, enchiladas, etc.) and more elaborate chicken, beef and seafood dishes. We found ups and downs in both categories.

Among the standards, the chile rellenos and spinach enchiladas are particularly good. The tacos aren't bad, either, although the chef had been a tad tightfisted with the meat filling. If you really want to taste your food, order the Mexican standards separately: Plata Grande hasn't solved the perennial combination platter problem, in which flavors, textures and sauces seem to fuse into a confusing, gloppy mess.

Chili verde is a lovely dish at this restaurant, with tender pork cubes in a piquant sauce of green chili peppers. The red sauce in the chili Colorado is more mundane. The chicken on two recent visits was chewy and dry, served in a pleasant, sesame-flavored sauce in a dish called pipian, and in a grossly oversalted, peanut-based sauce in mole de cacahuate .

The paella is pleasant, but seafood lovers probably would be more pleased with the cazuela de marisco , a heartier and more meaty seafood stew. Shrimp in garlic butter are excellent: fresh and tender, and the portion is generous.

The best dessert in the house is mil hojas, a marvelous, crackly pastry filled with a velvety vanilla cream. The worst is sopapillas , the heaviest, pastiest version we've ever eaten. Somewhere in between is the fried ice cream, with an admirably light batter but covered by awful, imitation whipped cream.