Newport Beach or Sun Valley?

Only one of these is a beach destination. Newport Beach has a long stretch of sand down the Balboa Peninsula, from the surf by the piers and the dangerous waves of the Wedge to the calmer coves of Corona del Mar and the paddling strips inside the harbour. The Pacific stays cool, though, so most people come with a board or a wetsuit rather than to float.

Sun Valley is hundreds of kilometres from the sea. Summer swimming means the cold, sandy shore of Redfish Lake an hour north, the odd river eddy, or a heated pool.

Newport Beach eats better and more widely. Harbour dining rooms with boat views, brunch in Corona del Mar and fish tacos by the sand cover the town itself, and Costa Mesa and Little Saigon in Westminster, with its renowned Vietnamese cooking, add real range within a short drive.

Ketchum does well for its size, with après-ski grills and a few serious kitchens cooking trout, lamb and elk, plus a summer farmers' market. But it remains a small resort town, and some places shorten their hours in the quiet seasons.

Neither is a sightseeing destination, and an afternoon covers most of what each has. Newport has a little more: the 1905 Balboa Pavilion, Schindler's Lovell Beach House for architecture lovers, Sherman Library & Gardens, and a proper art museum next door in Costa Mesa.

Sun Valley's interest is in its story, as America's first destination ski resort with the first chairlifts, the Lodge's corridors of film-star photographs, and Hemingway's grave and memorial in Ketchum.

Newport offers more of an evening, split between loud beach and dive bars by the piers on summer weekends and wine bars and hotel lounges around the harbour. There are no real clubs, and serious nights out mean Costa Mesa or Los Angeles.

In Sun Valley, going out is après-ski in a handful of Ketchum saloons and lounges, with a couple of western bars that stay loud until closing. Outside the ski season and midsummer, the night is usually over soon after dinner.

Sun Valley is the stronger pick for the outdoors. Bald Mountain's long fall-line runs, groomed Nordic trails and backcountry touring fill the winter, and in summer the same hills turn into singletrack and hiking routes, with fly fishing on the Big Wood and Silver Creek, rafting on the Salmon and the alpine lakes of the Sawtooths an hour north.

Newport's nature is coastal and gentler: the estuary loop of Upper Newport Bay with its winter shorebirds, bluff and canyon trails in Crystal Cove State Park, kayaking in the harbour and whale-watching boats all year. Real mountains are an hour inland.

Newport sits in the middle of Southern California, so the choice of outings is wide: Laguna Beach and Mission San Juan Capistrano are close, the ferry from Balboa reaches Catalina Island in about an hour, and Los Angeles and San Diego are both within reach, traffic permitting.

Sun Valley is surrounded by wild country rather than towns. Hailey's old main street and the log-cabin outpost of Stanley are the main stops, Shoshone Falls is about two hours away, and most days out lead into the mountains instead.

Newport Beach is much easier with children. Shallow harbour water, the Balboa Fun Zone's ferris wheel, the little car ferry, tide pools and whale watching cover the days, and Disneyland and Knott's Berry Farm are about half an hour away, at the cost of time in the car.

Sun Valley works well for families who ski, thanks to a separate beginners' hill and a good ski school, and summer brings horse rides, fishing and an outdoor rink. Nothing is built just for children, though, and altitude, cold and rainy days can make it hard going.

Sun Valley is the easier place to be without a car, at least within the resort. Ketchum's small grid is walkable, a free bus links the town, the village and the lift bases, and a bike path runs down the valley. Reaching trailheads, hot springs or the Sawtooths still means driving.

In Newport a car is close to essential, because the town spreads along the coast and up the hills and buses are sparse. Only the flat Balboa Peninsula and Balboa Island, joined by the little ferry, really work on foot or by bike, and beach parking is tight on summer weekends.

Newport is far better for shopping, especially for luxury brands. An open-air centre above the harbour has department stores and designer names, one of the country's largest luxury malls is ten minutes away in Costa Mesa, and Corona del Mar, Marine Avenue and the peninsula's surf shops fill in the smaller end.

Ketchum's few blocks offer art and western art galleries, good ski and fly-fishing gear, and some upmarket boutiques. That makes it a place for a painting or new waders rather than a day of shopping.

Both are costly, and neither offers a cheap way in. Newport's resort hotels and view restaurants charge heavily, and car hire, fuel and parking add to the bill, though staying in Costa Mesa or Irvine and eating tacos helps.

Sun Valley's prices are set by its wealthy second-home owners, with lift access on top and very little budget lodging. Coming in spring or autumn, staying down the valley and using the free buses are the main ways to save.

Newport has the better access to performance all year, mainly because the Segerstrom Center for the Arts is ten minutes away in Costa Mesa, with touring musicals, ballet, the Pacific Symphony and South Coast Repertory's new American plays next door.

Sun Valley's offer is concentrated in summer, but it is memorable: the free Sun Valley Music Festival brings a full orchestra to the pavilion by the lodge, with picnics on the lawn, and star skaters perform on the outdoor rink. The rest of the year is very quiet.

The two are fairly even, but the rest they offer is different. Newport's calm comes from bluff walks, harbour coffee and sunsets over the Pacific, with resort spas, day spas and yoga studios around Corona del Mar and Fashion Island, though the peninsula gets crowded on summer weekends.

Sun Valley edges ahead for soaking. Outdoor heated pools under falling snow are a highlight, and up the Warm Springs valley there are rough natural hot springs beside the creek, something the coast has no equivalent for.