Each time I dined at Rosa Mexicano, the vast newcomer that has instantly quickened the pulse of 6th and Hennepin in downtown Minneapolis, I could hear the words of a professor of mine as he offered his assessment of my study group's presentation. "Next time, give me less show and more substance," he said. In hindsight, Dr. Smith was mostly wrong -- he gave us a B, after all -- just as I would be mostly wrong if I were to make the same assessment of this fast-growing chain.

It is definitely wrapped up in an eye-grabbing package. Rosa's upscale intentions announce themselves immediately, with stylish and energetic surroundings that not only wipe away all thoughts of middlebrow Chi-Chi's (a previous tenant) but every standard-issue mom-and-pop Mexican restaurant setting. Unlike the Brazilian steakhouse next door, which could have been plucked directly off the hermetically sealed corridors of the Mall of America, Rosa not only celebrates its urban address, it flaunts it, despite its location in one of downtown's ugliest buildings, the City Center parking ramp. How great is that?

Enormous windows, covered in shimmering, see-through curtains, reveal a long expanse of sidewalk seating that will undoubtedly become prime Twins territory next spring. Inside, the main dining room could double as the city's hottest nightclub. It's bathed in flattering pink light and anchored by a soothing cobalt-tiled pool of water that's topped by a mobile of miniature cliff-diving dolls, one of the company's many visual trademarks. Spend 10 minutes in this splashy, sexy environment -- it's the work of Seed Design of New York City and Shea Inc. of Minneapolis -- and you'll think, yeah, this is how a downtown restaurant should look.

Another extravagant showbiz moment is the tableside guacamole preparation. It's the Mexican version of those crazy mushroom-tossing teppanyaki stations that were once the rage at Japanese restaurants. It's harmless fun wrapped up in a learning moment: Not only do staffers demonstrate the most expedient way to gut an avocado, but the process guarantees eyewitness knowledge of the guacamole's freshness. It's delicious, by the way, although my taste buds longed for an acidic lime bite, but that's just me; there are countless ways to prepare guacamole, and this version is more than satisfying.

Mexico, by way of New York City

Rosa's roots are in Manhattan's Upper East Side. When it opened in the early 1980s, contemporary Mexican was a near-radical dining concept. As the company has grown during the past decade -- its 13th location is opening soon in suburban Washington, D.C. -- I can't help but wonder if the kitchen's most distinctive aspects are being smoothed over by the inevitable creep of corporate sameness.

Some dishes can't help but stand out. An enormous pork shank was crispy on the outside, mouth-meltingly tender inside, with each bite exuding a teasing heat. There's an excellent chile relleno, stuffed with more of that delicious slow-cooked pork. Pork belly-scallop tacos, dressed with a cool orange-habanero salsa, were a deluxe surf-and-turf treat.

Rolled chicken tacos, beautifully seasoned, lived up to their claim of crispiness. I loved the roasted bone marrow, its gooey richness liberally spread on garlicky toasts and finished with a nicely matched sweet-hot sauce. A yellowtail tartare was nothing short of gorgeous, its succulent flesh as pink as the room, and its velvety texture accented with cool pops of cucumber and watermelon. Short ribs were a knockout, and red snapper and salmon were both treated memorably. It's not often that fresh huitlacoche -- also known as corn smut -- makes its way onto a Minnesota menu; don't miss it in the melted cheese-mushroom fondue.

Up and down

The deeply flavorful salsas and molés were nurtured with obvious care. I'd recommend the well-constructed noon-hour sandwiches, and weekend brunch was pleasant enough. But much of the cooking exhibited far less passion, coupled with a less-than-stellar skill set: rubbery shrimp, a dull tortilla soup, standard-issue quesadillas, a lifeless chicken tortilla pie. Enchiladas and tacos all begin to blur together, flavor-wise, and many dishes tasted as if they had languished under heat lamps, an issue for kitchens simultaneously servicing hundreds of guests. Some parts of the menu seemed to have been crafted by committee: A tuna-and-fruit salad would feel right at home in a corporate campus cafeteria, and a filet mignon was an inauthentic appeal to the steakhouse crowd. At least there isn't a burger.

Is the menu too large? Probably. And maybe too gimmicky, often at the expense of expertise. Churros are hustled to the table in a paper bag -- pink, of course -- and are given a theatrical shake in cinnamon and sugar before being carefully emptied onto a plate. It's amusing enough, but the laughs end when a bite into the wonderfully crispy, piping-hot doughnuts reveal raw batter. As for the remaining overwrought desserts, they could use some judicious editing and a lot less sugar.

The well-trained and accommodating service staff is a definite asset. Ditto the scrupulously tended bar. Ironically, the most aggressively pushed cocktail is its least interesting effort, a frozen, pre-made and pink (naturally) pomegranate margarita that's a sort-of south-of-the-border Cosmo. The carefully crafted margaritas, beer cocktails and refreshing alcohol-free aguas frescas are all first-rate.

And not inexpensive. That's a caution about Rosa Mexicano: The tab can escalate, fast. Seriously, $14 guacamole (or $28, for a double shot)? A $13 margarita? Nine bucks for over-refrigerated chocolate flautas? I'm skeptical, value-wise. But those prices make sense. After all, a coast-to-coast expansion doesn't come cheap.