What's in a name? Usually very little. But with theirs, nouvelle-Mexican spot Alto Bajo makes its ambitions and limits explicit.

In the polished pastel interiors of downtown's new Hi-Lo Hotel, Alto Bajo ("high-low") has translated a brand-conscious luxury hotel into Spanish. The restaurant is beautiful in the way that furniture stores can be beautiful—a blonde-wood nest of patterned booths and hanging baskets with a sparse plant museum of cactus.

(Abby Gordon)
(Abby Gordon)
(Abby Gordon)
(Abby Gordon)

But alto and bajo are also everywhere at Alto Bajo. Former Moto and Acadia chef Chip Barnes has created a menu with vertiginous peaks and valleys, from a poblano relleno that's one of my favorite new dishes this year to a parched husk of cochinita pibil that cost $36 and failed at every level of execution. Here are the highs and the lows.
THE ALTO:

That poblano relleno ($13) is a masterpiece. Stuffed into an earthy, roasted poblano is a seasonal tour of texture and flavor: bright apple with cranberry or cherry,  the low richness of smoked goat cheese and the satisfying bittersweet crunch of marcona almonds (now pecans), balanced by lovely carrot or tomato sauce. It's like a South-of-the-Border harvest cornucopia, based on a chiles en nogada holiday dish.

(Abby Gordon)
(Abby Gordon)
(Abby Gordon)
(Abby Gordon)

Barnes' knack for delicate complexity also shows up in a masterful lamb-loin mole rojo ($29), balancing a trio of peppers and only wisps of chocolate, roasty smoke and sesame. The rojo and verde salsas in the tortilla-chip salsa duo ($6) are extraordinary in both depth and freshness, and the rich guac ($10) will nail you to your seat. Pair with one of the margaritas ($11-$14), including a sweetly friendly prickly pear ($12).
THE BAJO:

Service—which runs morning, noon and night—can be stretched thin. Otherwise excellent plates were served lukewarm, and we spent one night asking for our silverware back before waiting endlessly for the wrong bill.

(Abby Gordon)
(Abby Gordon)
(Abby Gordon)
(Abby Gordon)

The $36 cochinita pibil, meanwhile (now $23 in a smaller portion), arrived as a mammoth pile of pork on a banana leaf with a trio of simple sides. The famously moist, slow-cooked meat was instead desiccated, next to an equal pile of over-acidic pink onions. Though the broad platter was meant to serve many, it included only a small complement of tortillas that proved hilariously difficult to refill.

And while the upscale margarita variations are consistently pleasant if expensive, the mixology-forward drinks were too often unbalanced, whether the near-undrinkable mezcal smoke and ginger sharpness of a Oaxacan mule ($12), or the cloying agave-meets-ashtray sensation of a tequila-mezcal take on the old fashioned ($12).

This smoky unbalancing act continued into dessert: The flan was embellished with an aggressive smear of mezcal compote. Though I've had dishes there that rivaled the best versions in the city, I left with a funny taste in my mouth.

GO: Alto Bajo, 310 SW Stark St., 971- 222-2111, altobajopdx.com. Breakfast and lunch 6:30-10:30 am and 11 am-2 pm Monday-Friday.  Dinner 5:30-9 pm Monday-Thursday, 5:30-10 pm Friday-Saturday. Brunch weekends 7:30-2 pm.