For several years, a dedicated, highly partisan cult has been flocking – and dragging others – to the Upper East Side six evenings a week. Sushi of Gari, a spare nook on East 78th Street that is invariably crowded with its devoted adherents, has built up a reputation for inventive, pristine sushi. In January, chef and owner Masatoshi “Gari” Sugio opened an Upper West Side incarnation of the restaurant, with a full menu of cooked dishes buttressing the familiar raw fish offerings.

Burnished wood and modern lines give the new Gari a cleaner, prettier appearance than its older sibling, though some may miss the idiosyncrasy of the original. The new restaurant’s popularity means that its fanatical sushi-connoisseur clientele shares the space with a less discerning crowd, whose irreverent din may make it hard for devotees to lapse into a reverie over the sublime fish. Neighborhood professionals and tables of affluent high-schoolers shout for more spicy tuna rolls and hot sake; one solo diner I observed chatted intently on her cell phone for an hour, hardly transfixed by the chef’s choice dinner she was eating. And the restaurant’s design offers little solution to the symptoms of runaway fame: closely packed tables and hard, reflective surfaces heighten the raucous noise level, and the servers, assiduous though they are, seem overtaxed by the demanding hordes.

Sushi can be ordered either a la carte from a substantial list of fish (pieces and rolls run from $3 to $14), or in smallish composed arrangements. These include a basic sashimi plate ($28) or tuna-only platter ($26), as well as the omakase dinner, or chef’s choice, which highlights Chef Gari’s composed creations, and ranges in price, depending on the markets, from about $60 to $100. These are what made Gari’s name: prime little pieces of raw fish uniquely topped and seasoned, and beautifully presented. He dresses chewy, flavorful tangles of giant clam with a heady amber sauce of monkfish liver and turns delicate, thin-sliced seared tuna into a palate-awakening experience with a dab of jalapeno puree. A rich sesame sauce complements savory, fatty mackerel, while a piece of leaner, lighter red snapper gets a whole miniature salad on top: fresh baby greens, pine nuts, and a fried lotus-root chip. Hot, salty tomato puree tops warm raw salmon, in a startling Italianate twist, and an oniony, creamy tofu-based mousse is a superb foil for tuna.

These creations are on par with some of the city’s great sushi: elegantly balanced, with distinctly high-quality fish enhanced but never eclipsed by the artful preparations. The fish shines in the more traditional formats as well – marbled toro, unctuous yellowtail, and less usual sightings, like silver shad, are all excellently fresh and finely cut. The warm, discretely textured rice in nigiri and maki sushi excites the molecules of the cool fish, bringing out fuller flavors, and provides a subtle, pleasing contrast.

But the kitchen’s prepared dishes – a feature unique to the new restaurant – can be disappointing. They inhabit a less than wholly inspired Asian-fusion sphere: Finely chopped tuna tartare ($12), peppered with pine nuts and capers, could be served anywhere. The tuna, though good, lacks the brilliance of sashimi, and a mess of sweet infused oils on the plate mask rather than enhance it. Roasted beef short ribs ($13) in a sticky soy glaze, akin to Korean kalbi, are cut into two-bite bone-in morsels intended for handheld eating, but the flavorful meat is tough and stringy.

Main courses include a filet of Chilean sea bass ($26), the succulent, flaky tooth fish (whose de rigueur presence on a million menus has earned it “over fished and regulated” status). This is another conventional, undistinguished, if tasty, dish. The filet, seasoned with sake and Chinese-style fermented black beans, has rich, savory flavor and a crisp surface; the salty, lightly greasy sauce gives it a moist sheen. Duck breast ($28), sliced in a balsamic vinegar teriyaki sauce, is nicely seasoned but suffers just a bit from overcooking: The crisp-edged slices have a toughness that makes them less than appealing. An accompanying helping of mustard seed mashed potatoes falls flat, too: The starch is mealy and dry, and the mustard seeds add a harsh, bitter note.

A dozen or so sakes can be had, though their prices are overly high and bottles small. But the restaurant accommodates a range of budgets, with omakase- and sake-buyers at one end of the range, and, agreeably, an assortment of Japanese beers – Asahi, Kirin, and Sapporo (all $5) – to refresh those at the other end. A couple of red and white wines, served by the glass, round out the beverage offerings, along with a Lustau cream sherry ($5). The sherry, poured over vanilla ice cream, makes an unexpected dessert ($7), too, the best of the options; a couple of undistinguished chocolate cakes ($12 each) and unadorned scoops of ice cream ($3) make up the balance of the list.

The crowds of followers aren’t wrong: Chef Gari’s sushi is very good indeed, and his empire (there is a Sushi of Gari in Tokyo as well) has been ripe for expansion. Next to the greatness and inventiveness of the sushi, though, the prosaic cooked additions to the menu seem feeble and gratuitous. They could be improved – or the new restaurant could just concentrate on the strengths that have taken Gari this far, and that need no improvement.

Gari, 370 Columbus Ave., 212-362-4816.