Jackson Hole or Sun Valley?

Neither is a swimming destination. Both offer only cold mountain lakes for a few weeks in midsummer. The difference is in the details. Jackson's String Lake is shallow and warms enough for a real swim by late summer, right at the foot of the Tetons.

Sun Valley's best lake, Redfish, is an hour's drive away and stays cold, so heated outdoor pools are the more reliable swim there.

Both towns eat better than their size suggests, because wealthy visitors pay for ambitious kitchens. Jackson has a little more range and a clearer regional identity. Elk, bison and Rocky Mountain trout are often finished with huckleberries, and around the Town Square you find steakhouses, saloons and serious wine lists.

Ketchum cooks Idaho trout, lamb and elk well, but it has no regional dish to seek out. Some of its kitchens also shorten their hours in the quiet seasons.

Jackson has a little more to see. The National Museum of Wildlife Art is a real collection. The barns of Mormon Row and the log Chapel of the Transfiguration, framed by the Tetons, are memorable even if small, and the antler arches give the square its character.

Sun Valley's interest is in its history: America's first destination ski resort, the first chairlifts, a lodge lined with old film-star photographs, and Hemingway's grave in Ketchum. An afternoon covers it.

Jackson is livelier after dark. In winter, Teton Village fills with loud après-ski as the lifts close. In town, a saloon with saddle bar stools and a country dance floor, along with brewpubs and cocktail bars, keeps the evening going a while.

Sun Valley's nights are almost entirely après-ski in a handful of Ketchum saloons, wine bars and hotel lounges. Outside the main seasons, most evenings end soon after dinner.

Both are outstanding mountain bases, but Jackson is wilder and more dramatic. It has the Tetons, a national park on the doorstep, Yellowstone within reach, a tram to the steep terrain above Teton Village, and animals from grizzlies to wintering elk.

Sun Valley is more about the sports themselves. Bald Mountain has long, unbroken fall-line runs, the hills are threaded with singletrack, fly fishers come for Silver Creek, and the jagged Sawtooths lie an hour north. Elk are often seen, and the wider Wood River and Sawtooth country has its own animals, but wildlife watching is a smaller part of a stay here than in Jackson.

In both places the real excursions lead into the mountains, but Sun Valley has slightly more places to visit. These include Hailey's historic main street down the valley, the log-cabin outpost of Stanley beyond the Sawtooths, and Shoshone Falls on the Snake River about two hours south.

Jackson's options are quieter farm and ranch towns over Teton Pass or out towards Pinedale. None of them repays a full day.

Jackson is the stronger choice with children. Wildlife sightings, Junior Ranger programmes, gentle lakeside trails, scenic floats, winter sleigh rides through the elk herd, the rodeo and the staged shootout give plenty of variety. The catch is the long drives into the parks.

Sun Valley is easy and safe, and its separate beginner hill is a real advantage for small skiers. Beyond that and the summer pools, horse rides and ice rink, though, there is not much for non-skiing teenagers.

Jackson's centre is compact and walkable, and a bus runs out to Teton Village for skiing. Beyond that, the parks, trailheads and dawn wildlife drives all need your own wheels. Its airport sits just north of town, inside the national park.

Sun Valley is easier to manage without a car. A free bus links Ketchum, the village and the lift bases, and a paved path runs down the valley, so a whole ski week can pass without driving. The nearest airport, in Hailey, is close by but small, so many visitors fly into bigger airports and face a long drive that can be snowy in winter.

Both offer a few upscale blocks rather than real shopping, and the two are similar in kind. Jackson's boardwalks are stronger on Western identity, with wildlife and Western art galleries, handmade cowboy hats and boots, and turquoise jewellery. Ketchum leans towards cashmere, home decor and fly-fishing gear, and its galleries hold evening walks in the main seasons.

Neither offers any relief here. Both are priced for wealthy second-home owners and resort guests, from rooms to lift tickets. The ways to cut costs differ. In Jackson, the free trails and roadside wildlife are the bargain, along with lodging over the pass in Idaho. In Sun Valley, it is staying further down the valley and riding the free buses instead of hiring a car.

Both are summer-only for live music, but Sun Valley's festival is the bigger draw. A full orchestra plays in an open pavilion by the lodge, admission is free, and the audience picnics on the lawn. The long tradition of star figure skaters on the outdoor rink adds something unusual.

Jackson's Grand Teton Music Festival fills a timber hall in Teton Village. The town adds chuckwagon dinner shows and country bands in the saloons, giving it a more Western flavour.

The two are close, and both rest on hot springs and resort spas rather than any bathing tradition. Sun Valley feels slightly more restful. Steaming outdoor pools at the resort are close to hand, and there are primitive creekside soaks up Warm Springs.

Jackson's springs take more effort but make more of an outing. One is a forest canyon pool reached by snowmobile or dog sled in winter, and the other is a riverside park with several soaking pools.