Las Vegas or San Diego?

Las Vegas has no coast at all. The Mojave keeps the Pacific hours away, so swimming means a resort pool on the Strip or a drive to the gravel shore of Boulder Beach on Lake Mead, which sits in a desert basin with no shade.

San Diego's shoreline is the main reason many people go. It runs from Coronado's broad strand to the Mission Beach boardwalk and the gentle surf of La Jolla Shores. The Pacific stays cool, so expect a bracing swim except in late summer.

Las Vegas is the better choice for a grand meal. The resorts compete through their dining rooms, so a big steak dinner or an evening of French cooking is easy to book, and the famous buffets are part of the fun. Almost all of it comes from somewhere else, though, and it is priced for the resort, so you rarely feel you are eating anywhere in particular.

San Diego's food is more casual and more local. It takes its cue from the border, with Baja fish tacos eaten by the water and the California burrito, and its breweries in North Park and Miramar are worth a trip in their own right. Convoy Street and the Little Italy farmers' market add variety, but there are fewer special-occasion dinners to plan a trip around.

San Diego gives a curious visitor much more to do. Balboa Park alone puts the art, natural history, and air and space museums inside its exposition buildings. The USS Midway, the adobe buildings of Old Town and Mission San Diego de Alcalá add a real naval and colonial past.

The sights of Las Vegas are the themed resorts and the Fremont Street light show. Its history is limited to the old casino signs at the Neon Museum and the Mob Museum in the former courthouse. Both are well done, but a day or two is enough to see them.

This is where Las Vegas pulls well ahead. Resort clubs host star DJs, dayclub pool parties fill the afternoon, and the Strip is still full at three in the morning. Fremont Street and the arts district have cheaper dive bars and craft beer.

Nights out in San Diego are easier going and shorter. The Gaslamp Quarter and Pacific Beach get loud at weekends, and North Park and Hillcrest suit taprooms and cocktail bars. Last call at 2am ends most evenings around the time the Strip is at its busiest.

San Diego's outdoors can be enjoyed in every month. The ocean trails at Torrey Pines, the sea lions and sea caves at La Jolla Cove, the tide pools at Cabrillo and surf breaks all along the coast are close at hand. Inland are the oak and pine of the Cuyamaca Mountains and the badlands of Anza-Borrego.

Las Vegas has superb desert rock at Red Rock Canyon and Valley of Fire, with climbing among the best in the country, and pine forest on Mount Charleston. But summer heat rules out desert hiking except at dawn, and every outing needs a car.

San Diego has far more choice. Tijuana is a trolley ride and a walk across the border, and the Valle de Guadalupe vineyards lie further south. On the US side are Temecula's wine country, the apple-pie town of Julian and coastal towns you can reach by train.

From Las Vegas the one easy outing is Hoover Dam with Boulder City. The Grand Canyon, Zion and Death Valley are magnificent, but each is a long day out to see a landscape, not a varied set of trips.

San Diego is one of the best cities anywhere for families. It has the zoo, with its skyfari ride over shaded canyons, the giraffes and rhinos of the Safari Park, SeaWorld and Legoland for younger children. Balboa Park's lawns make a break between museums, and the weather rarely spoils a plan.

Las Vegas can fill a day or two with the indoor amusement park, the shark aquarium and the fountain show. But children are walked past casino floors and adult advertising, and summer heat makes walking hard. Most families pass through on the way to the national parks.

Neither city is easy without a car, but for different reasons. In Las Vegas the Strip looks walkable, but the walks stretch through huge resorts, footbridges and casino interiors. A monorail and buses that run day and night are the alternatives.

San Diego has a walkable core in downtown, Little Italy and the Gaslamp Quarter, with a trolley to Old Town and the border and coastal trains north. But La Jolla, the beaches and the theme parks are spread far apart.

Las Vegas is better for a shopping trip if big brands are the aim. It has the Roman-themed arcade at Caesars Palace, the Venetian's canal-side shops, the luxury mall in the middle of the Strip, Fashion Show and two outlet centres, all open late.

San Diego has fewer big names, mainly at Fashion Valley and the outlet centre by the border, but more local character. There are independent and vintage shops in North Park and Little Italy, galleries in La Jolla and Mexican pottery in Old Town, none of which Las Vegas has.

Las Vegas leaves more room to save, provided you go midweek. From Sunday to Thursday, rooms on the Strip and downtown can be good value for their comfort, and meals in Chinatown are reasonable. Weekends, resort fees, shows and clubs push costs up quickly, though.

San Diego is expensive throughout. Beach and downtown hotels cost a lot in summer, the big family parks charge high admission, and a hire car adds parking. Taco shops, free beaches and the gardens of Balboa Park are the best ways to keep spending down.

Las Vegas is the place for spectacle. Water-based acrobatic shows, magicians, comedians, and pop and country stars on long residencies add up to dozens of shows on any night, and the Smith Center hosts touring Broadway musicals.

San Diego's strength is serious theatre on a much smaller scale. The Old Globe and the La Jolla Playhouse produce shows that have gone on to Broadway. The symphony's summer season on the waterfront and free organ concerts in Balboa Park add to the programme.

Neither city has a bathing tradition, so the difference lies in the setting. Las Vegas has some of the largest hotel spas in the country, with thermal circuits and salt rooms, but they sit in casinos that never go quiet. A weekday morning at a hotel without a casino is the best way to use them.

San Diego has fewer grand spas but a slower pace. There are resort spas in La Jolla and Coronado, the yoga and meditation culture of Encinitas around its clifftop gardens, and quiet mornings in the beach towns.