Phoenix or Santa Monica?

This is where the two cities differ most. Santa Monica sits on a wide sweep of pale sand, with the pier at its centre and lifeguard towers along its length. Quieter, more scenic beaches lie north at Zuma, El Matador and Point Dume. The Pacific is cool, so expect wading more than long swims, and avoid the water right by the pier.

Phoenix has no coast within easy reach. Water there means the resort pool or a day out to Saguaro Lake or Canyon Lake among bare desert cliffs. In summer you can also go tubing on the lower Salt River.

You will eat about equally well in both places, but the food is very different. Phoenix's strength is Sonoran borderland cooking: carne asada, machaca, paper-thin flour tortillas and bacon-wrapped hot dogs from evening carts. It also does wood-fired pizza and serious bread. The catch is that the best places are spread across the south and west of the city.

Santa Monica eats from the farmers market. Expect seasonal Californian plates, seafood, brunch and good Italian and Japanese restaurants along Main Street and Montana Avenue. What it lacks is the cheap immigrant cooking that Phoenix's Mexican kitchens provide.

Neither city is for wandering old streets, but Phoenix has more to see. The Heard Museum is a major collection of Native American art, the Musical Instrument Museum can fill an afternoon and Taliesin West shows Frank Lloyd Wright's desert work. Each one is a separate drive.

Santa Monica's own sights stop at the pier, Bergamot Station's galleries and some Art Deco buildings near the ocean. Its best culture lies just outside town, at the Getty Center on its Brentwood hilltop and the antiquities of the Getty Villa.

Phoenix offers more of a night out, though you have to choose one area and stick to it. Old Town Scottsdale has clubs and rooftop dance bars that fill with weekend groups. Mill Avenue in Tempe runs on students, and Roosevelt Row has craft beer and cocktail bars.

Santa Monica is for a sunset drink, not dancing. Expect wine bars and rooftops near the Promenade, pubs on Main Street and a looser crowd in Venice. If you want clubs, you have to take a long ride to Hollywood.

Both are strong outdoor bases, but the landscapes are very different. Phoenix is Sonoran desert: steep scrambles up Camelback and Piestewa Peak, the huge park at South Mountain and saguaro forest in the McDowell Preserve. The red rocks of Sedona are within reach, but the summer heat confines all of this to the cooler months.

Santa Monica combines coast and canyon. Trails through chaparral and oak climb into the Santa Monica Mountains from Temescal and Topanga, and a 35km paved path follows the beach. There are surf lessons and whale-watching too, and the mild climate makes it usable all year.

Santa Monica has more varied outings. You can drive the coast to Santa Barbara's mission and wine country or south to Laguna Beach's coves, or take the ferry to Avalon on Catalina. Within Los Angeles there is the Huntington in Pasadena, though traffic decides how much you see.

Arizona's distances keep Phoenix's list shorter, but it has a frontier character. Jerome is an old mining town on a hillside, Montezuma Castle is a cliff dwelling and Tucson has adobe barrios and Mission San Xavier del Bac. The Grand Canyon is too far for a comfortable day.

Santa Monica makes things easier with children. The lifeguarded beach is good for digging, and the pier has a Ferris wheel, a carousel and a small aquarium. A flat path is good for family bike rides, and the compact town keeps travel short. Theme parks, though, take up a full day in traffic.

Phoenix has the zoo, a science centre, water parks and resort pools with slides, plus spring training baseball in March. It works well in the cooler months, but expect long car journeys between attractions and summer heat that is risky for young children.

The gap here is wide. In Santa Monica you can walk between downtown, the pier and Main Street, cycle the beach path and take the blue buses. The E Line light rail goes to downtown Los Angeles. A car is needed only for the Getty, Malibu canyons and Hollywood.

Phoenix is a flat grid of arterial roads, with its districts and trailheads tens of kilometres apart. The single light rail line between the airport, downtown and Tempe helps within that corridor, but most visitors rent a car from day one.

Santa Monica has somewhat more interesting shopping. Montana Avenue has boutiques, Main Street has surf shops and Abbot Kinney in Venice has design-led stores. The Promenade covers the chains, and Rodeo Drive is not far.

Phoenix is built around malls, with luxury brands in Scottsdale and near the Biltmore. Its standout buy is Navajo and Zuni silver and turquoise, Hopi carvings and pottery from museum shops and reputable galleries. Santa Monica has nothing to match it.

Phoenix is clearly the cheaper of the two. Freeway chain hotels are good value all year, and summer resort rates fall sharply. Its Mexican food is cheap and hiking is free, so the main extra cost is a rental car.

Santa Monica is expensive even for California. Rooms near the ocean and restaurant bills are high, and parking adds more. Free beaches, the bike path and cheap buses help, as does staying a little inland.

Phoenix has the fuller programme within the city itself. The symphony, Arizona Opera and Ballet Arizona all run seasons, and touring Broadway comes to Wright's round ASU Gammage. The Musical Instrument Museum has its own intimate concert hall. Almost everything happens between autumn and spring.

Santa Monica's own stage is smaller: the Broad Stage, small playhouses, a long-running folk and acoustic scene and free summer concerts on the pier. The big names are a cross-town drive away, at Disney Concert Hall and the Hollywood Bowl.

Phoenix is better for a proper rest. It is one of America's classic resort destinations, with full-service spas, several pools and golf courses below Camelback, and treatments using desert ingredients. Dry winter warmth makes a week by the pool easy, though the best of it costs resort money.

Santa Monica's version is more active and do-it-yourself: yoga on the sand, a morning run by the ocean, a hotel spa and sunset over the bay. Neither city has hot springs or a public bathing tradition.