Big Sky or Sun Valley?

Neither place is for swimmers, but Sun Valley has a little more to offer. In midsummer people drive an hour north to Redfish Lake under the Sawtooths, which has a real sandy shore even though the water stays cold.

Big Sky has nothing like it. The Gallatin is a fast, rocky river, the local ponds are good for a paddle at best, and a hotel pool is the most likely place you will swim.

Sun Valley eats better, mainly because its restaurants are gathered in Ketchum, a real small town with a mix of après-ski grills and a few ambitious kitchens. In summer there is a farmers' market and dining on patios.

Big Sky's restaurants are spread across Mountain Village, Town Center, Meadow Village and the roadhouses in the canyon. The cooking is hearty bison, elk and trout with a local brewery scene, and for more variety people drive an hour to Bozeman. Both resorts have high prices and kitchens that close between seasons.

Neither resort is a sightseeing destination, but Sun Valley has a story to tell. The Union Pacific railroad built it in 1936 as America's first destination ski resort, the Lodge's corridors are lined with photographs of film stars, and Hemingway is buried in the Ketchum cemetery.

Big Sky dates from the 1970s and is mostly timber-clad condos. Its one piece of heritage is the pair of log cabins at the Crail Ranch homestead in Meadow Village.

Evenings are much the same in both: après-ski, an early night and no clubs at all. The difference is the setting. In Big Sky the crowd in ski boots gathers on the sunny decks at the foot of the lifts, and later the old canyon saloons offer pool tables and a ranch-country crowd.

In Sun Valley you go down into Ketchum, where you can walk between saloons, wine bars and hotel lounges. A couple of old western bars there stay loud until closing time.

Both are first-rate outdoor destinations, and the difference is in kind rather than quality. Big Sky is the bigger mountain: Lone Peak rises to 3,403m above a vast ski area, the Spanish Peaks and Lee Metcalf Wilderness are on the doorstep, and Yellowstone's geysers, bison and wolves are a day out.

Sun Valley's Bald Mountain rises straight out of town, with steep runs that drop down the fall line and dry snow under sunny skies. In summer you get dense singletrack, the alpine lakes of the Sawtooths, the spring creek at Silver Creek and the gold of autumn aspens.

Big Sky has more to drive to. Bozeman is an hour down the canyon, with a Western main street and the dinosaur fossils of the Museum of the Rockies. Further out, the preserved 1860s boardwalks of Virginia City and Nevada City and the old railway centre of Livingston are within reach.

From Sun Valley the choice is thinner. There is Hailey's small main street, the log-cabin outpost of Stanley, and Shoshone Falls about two hours south. Boise is too far for an easy day.

Big Sky gives children more to do. The summer adventure park has zip lines, ropes courses and gondola rides, and there is horse riding, gentle rafting and bison-spotting in Yellowstone.

Sun Valley is easy and safe, with a separate beginner hill, an outdoor ice rink and bike paths, but nothing there is built just for children, and teenagers who don't ski may get bored. In both places a rainy day is hard to fill and the altitude takes some getting used to, more so at Big Sky's 2,300m base village.

Sun Valley is easier to get around. Ketchum's small, flat grid is walkable, a free bus links the town, the village and the lift bases, and a paved bike path runs down the valley. Hailey's small airport is close by.

Big Sky is strung along about 15km of road, so each village is walkable but you can't walk between them. Bozeman airport is an hour away, and you need a car for Yellowstone. Beyond the resort, both places depend on driving.

Sun Valley has the better shopping, all within a few blocks of Ketchum. There are fine and western art galleries with evening walks, good fly-fishing and gear shops, and boutiques selling cashmere and home decor to second-home owners.

Big Sky's shops cover the basics, such as gloves, a fly rod or a wildlife painting. For anything more, people drive to Bozeman.

Both are among the costliest mountain trips in the West, so neither suits a tight budget. The difference is in how you save. At Big Sky, staying in the canyon or in Bozeman cuts the cost but adds a lot of driving.

In Sun Valley, you can stay further down the valley and still rely on the free buses. Coming in the quiet spring or autumn months also eases the bill.

Sun Valley has the bigger stage. For several weeks each summer the Sun Valley Music Festival brings a full professional orchestra to the pavilion by the lodge, with free admission and picnics on the grass. On summer evenings there are also ice shows on the outdoor rink, a tradition from the resort's early years.

Big Sky offers less, but it covers both seasons. A small arts centre in Meadow Village hosts touring musicians and theatre in winter, and in summer there are free lawn concerts and a short classical festival.

Sun Valley is the better place to unwind. It has big hotel spas and outdoor heated pools, and natural hot springs are close by: rough soaks beside the creek up the Warm Springs valley, and a simple pool north of town.

Big Sky's idea of rest is a hot tub on the deck, a massage for sore ski legs and quiet, starry nights. Its nearest natural springs are an hour away towards Bozeman.