Scottsdale or Sun Valley?

Neither place has a coast, so the choice comes down to the kind of fresh water and the pools. Scottsdale's water days are warm ones: hotel pools, sandy coves at Saguaro and Canyon Lakes, and tubing on the Salt River in summer.

Sun Valley's lake swimming happens at Redfish Lake under the Sawtooths, which is beautiful but cold even in August. Its heated outdoor pools are the more dependable option.

Scottsdale has the wider table. It offers steakhouses, sushi, patio grills and brunch in Old Town, and the more characterful food is Sonoran Mexican, with carne asada and green chile in family places across the wider Phoenix area.

Ketchum eats well for a small town, with trout, lamb and elk at its more ambitious kitchens. Still, the range is limited, cheap meals are hard to find and some places cut their hours in spring and autumn.

Scottsdale gives a curious visitor much more to see. Frank Lloyd Wright's Taliesin West is a genuine architectural landmark, the Museum of the West and the contemporary art museum are close by, and the Heard Museum and the Musical Instrument Museum are a short drive away.

Sun Valley's heritage is a footnote, though an interesting one: America's first destination ski resort, the Lodge's corridors of film-star photographs and Hemingway's grave in Ketchum. All of it fits into an afternoon.

Scottsdale has a real night out, all of it in Old Town's entertainment district. There are dance clubs, rooftop lounges and bottle service, loud and dressed-up on weekends and in spring.

Sun Valley offers après-ski and little else. You get a drink in a Ketchum saloon or hotel lounge, sometimes a band in winter, and an early night once the season ends.

Sun Valley is the place to go for the outdoors in its own right. Bald Mountain's long fall-line runs, Nordic and backcountry skiing, summer singletrack, fly fishing on the Big Wood and Silver Creek, and the alpine lakes and rafting of the Sawtooth and Salmon country make up a full mountain playground in both seasons.

Scottsdale's desert is a real asset too. The McDowell Sonoran Preserve's saguaro trails and quick climbs up Camelback and Pinnacle Peak are excellent. In summer, though, the heat restricts it all to dawn starts.

Scottsdale is the better base for days out. Sedona's red rock, the Montezuma Castle cliff dwelling and the old mining town of Jerome lie on one road north, with Tucson and the San Xavier mission to the south and Goldfield's ghost town for a short outing.

From Sun Valley, most excursions lead into the mountains, not to other towns. Stanley's log-cabin setting and Shoshone Falls are the main drives, and Boise is too far for an easy day.

Scottsdale makes the easier family trip. Resorts with lazy rivers and kids' clubs, the miniature railway park, the aquarium and butterfly house and the Phoenix Zoo fill days without effort, though summer heat keeps children indoors after midday.

Sun Valley suits families who already ski or hike. Its beginners' hill and ski school are excellent, but with nothing built for children, wet days and non-skiing teenagers are hard to entertain.

Sun Valley is simpler to get around without a car. Ketchum is flat and walkable, a free bus connects the town, the village and the lift bases, and many skiers never drive all week. A car is still needed for the hot springs and the Sawtooths.

Scottsdale is built along wide roads for driving. The light rail stops short of it, so apart from Old Town and its free trolley, nearly everything takes a hire car or a ride-hail.

For shopping, Scottsdale is a destination in itself. A luxury mall with the big fashion houses sits alongside open-air centres and an Old Town gallery quarter with high-quality turquoise, silver, pottery and western boots.

In Ketchum the shopping fills a few blocks of art galleries, fly-fishing and ski shops and boutiques for second-home owners. The gear is good, but the choice is small.

Both are upmarket resorts, but Scottsdale gives a careful traveller more room to save. Resort rates drop sharply in the summer heat, chain hotels and motels line the main roads, Mexican food is cheap and plentiful, and the desert preserve costs nothing.

Sun Valley has little budget lodging. Its second-home wealth sets the price of meals, rooms and lift access, so even staying further down the valley in the quiet months only softens the bill.

Scottsdale and its neighbours keep the stages busy for more of the year. There is chamber music, jazz and comedy at the Old Town arts centre, world music at the Musical Instrument Museum, and the symphony, opera and ballet in Phoenix.

Sun Valley's performances are concentrated in summer, when it does them memorably. The free music festival brings an orchestra to the lawn by the lodge, and figure skaters perform outdoors. The rest of the year there is very little.

Scottsdale is built around this kind of rest. It has a dense cluster of large resort spas, many open to day guests, plus dry air, palm-lined pools and easy access to yoga and retreats.

Sun Valley offers something rougher and more outdoorsy. You can soak in a heated pool under falling snow or in the undeveloped creekside hot springs up Warm Springs, and the hotel spas are there for a quiet day after skiing.