Atlantic City or Chicago?

Atlantic City's beach is the whole reason the place exists. A wide, free strip of pale sand runs the length of the island under the Boardwalk and carries on, quieter, through Ventnor and Margate. The open Atlantic is warmer at its peak, but surf and rip currents mean you swim between the flags.

Chicago's beaches come as a pleasant surprise rather than a reason to go. Oak Street and North Avenue are freshwater strands with the skyline right behind you. The lake can turn cold overnight when the wind shifts, and the swimming season is a little shorter.

Chicago is a food destination in its own right. It has its own canon of deep-dish and tavern-cut pizza, Italian beef and fully dressed hot dogs, a strong fine-dining row in the West Loop, and whole neighbourhoods cooking Mexican, South Asian, Vietnamese and Polish food. You could plan a trip around eating there.

Atlantic City feeds you well enough without becoming a reason to come. There are casino steakhouses and buffets, red-sauce Italian in Ducktown, giant subs, boardwalk pizza, crab shacks on the back bays and saltwater taffy. It is enjoyable seaside eating with far less range.

Chicago is one of the world's great architecture cities, the place where the skyscraper took shape. A river cruise past the towers of the Loop, Wright's Robie House and the Impressionists at the Art Institute can fill several days, and the lakefront museums add natural history and astronomy.

Atlantic City's heritage is the American seaside resort itself: the original Boardwalk, the street names from the Monopoly board, the Art Deco Boardwalk Hall and Lucy the Elephant in Margate. It is charming Americana, but it fits into a single day.

Chicago is much the better night out. In Atlantic City the night stays inside the casinos, where gaming floors and lounges never close and the resorts run nightclubs and pool parties on summer weekends. Step outside and the blocks between the towers are empty. Midweek or in winter the whole town goes quiet.

Chicago spreads its nights across whole neighbourhoods. There are cocktail and dive bars in Wicker Park and Logan Square, dance clubs in River North, the bars of Northalsted, the city's main gay district, and a loud sports-bar crowd around Wrigley Field. Many bars pour until 4am, the dance floors still carry the city's house-music roots, and in winter the night simply moves into warm old taverns.

Neither city has hills or dramatic scenery, but Chicago's lakefront gives it the edge for a day outdoors. A shore path of about 29km is made for walking, cycling and skating, and the parks along it sit on a bird migration route. The dunes of Indiana Dunes and the sandstone canyons of Starved Rock are both within reach.

Atlantic City's outdoors are marsh and back bay. The Forsythe wildlife refuge is good for herons and shorebirds, the bays suit kayaking and crabbing, and the Pine Barrens inland have sandy forest trails and canoeing. It is pleasant, especially for birders, but more of an extra than a draw.

Atlantic City has the better outings. Philadelphia, with Independence Hall and the Liberty Bell, is about an hour and a half away, and Cape May's Victorian streets are about an hour south. The boardwalk towns of Ocean City and Wildwood and the old ironworks village of Batsto are closer still.

Chicago sits on the open prairie, so most escapes take more effort: Milwaukee by train, Lake Geneva or the Michigan harbour towns by car. Oak Park's Wright houses make the easiest half-day, but nothing on the list rivals a day in Philadelphia.

With children, Chicago is far the stronger choice. It has the coal mine and U-boat at the Museum of Science and Industry, dinosaurs and belugas side by side on the Museum Campus, a free lakeside zoo, and Navy Pier and the climbing walls of Maggie Daley Park. Much of it is indoors, which helps when the weather turns.

Atlantic City offers a free, lifeguarded beach, the rides on Steel Pier and a climb inside Lucy the Elephant. Beyond that the city is built for adults, and casino floors are closed to under-21s. Many families stay in Ocean City or near Wildwood's piers instead.

Chicago is easy without a car. The L runs from both airports into the Loop, and the flat, gridded centre puts the main sights within walking distance of each other. Crossing between neighbourhoods often means a bus, though, and the January wind makes walking a chore.

A visit to Atlantic City runs in a straight line along the Boardwalk, with jitneys up and down Pacific Avenue around the clock. Leave that strip for the refuge, the Pine Barrens or Cape May and you need a car, and the streets inland are not pleasant to walk at night.

Chicago is a real shopping city. Flagships and department stores line the Magnificent Mile, luxury labels gather on Oak Street, and the old Marshall Field's building still trades under its Tiffany ceiling. For independent shops there are Wicker Park, Bucktown and Andersonville.

Atlantic City has an outlet district, casino arcades and Boardwalk souvenir stands. Its saltwater taffy is the one thing that is truly its own.

Atlantic City is the cheaper of the two, as long as you avoid summer weekends. Casino hotels discount rooms heavily midweek and out of season, and the beach, the Boardwalk and much of the entertainment cost nothing. Resort fees, parking and tips still add up.

Chicago is expensive, with costly downtown hotels, high taxes and pricey sit-down meals. Taquerias, hot dog stands, good-value trains and the free lakefront soften the bill, and so does staying outside the Loop.

Chicago is one of the great performance cities in the country. It has the Chicago Symphony Orchestra and the Lyric Opera, the Goodman and Steppenwolf alongside dozens of storefront theatre companies, and nightly improv in the Second City tradition. Electric blues and late jazz sets play in its own clubs, and summer brings free concerts in Millennium Park.

Atlantic City's stages are arenas and casino showrooms for touring headliners, comedians and tribute acts, plus big concerts at Boardwalk Hall. With no orchestra or theatre district, you go for a particular show rather than for a scene.

Neither city is a place to unwind, though the ways to relax differ. Atlantic City offers casino hotel spas with saunas and indoor pools, and its real calm comes from a near-empty Boardwalk beside the winter sea.

Chicago has more character. There is a Russian-and-Turkish bathhouse in Wicker Park dating from the early 1900s, a Korean-style jjimjilbang in the suburbs, and warm conservatory glasshouses for a cold winter morning.