Chicago or Ocean City, Maryland?

Ocean City is a real beach resort and Chicago is not. Here the beach is the whole point: about 16km of soft Atlantic sand, a beach access at the end of almost every street, lifeguards along the full length and enough surf for bodyboarding. If the southern blocks feel crowded, Assateague's undeveloped shore is a short drive away.

Chicago's lake beaches are a genuine pleasure, and swimming in fresh water with the Gold Coast towers behind you is something no ocean town offers. But the water stays cooler, the swimming season is only a few weeks long and a change of wind can chill the lake overnight. They are for an afternoon off, not for a whole trip.

Chicago eats on another level. It has its own local classics, from deep-dish and tavern-cut pizza to the fully dressed hot dog, and serious restaurants along Randolph Street. The bigger draw, though, is the neighbourhoods: Mexican cooking in Pilsen and Little Village, South Asian food on Devon Avenue, Vietnamese on Argyle Street.

Ocean City does one thing well, which is a messy, convivial blue crab feast with Old Bay and a pitcher of beer, followed by boardwalk fries and frozen custard. Beyond that, the choice is mostly diners, chains and bar food, and many kitchens close or cut back after summer.

These two are not close. Chicago is where the skyscraper grew up, and you can follow that story from the Rookery to Mies van der Rohe's glass towers and out to Wright's Prairie houses. The Art Institute and the Field Museum alone could fill several days.

Ocean City's heritage is its boardwalk, with its old hotels, wooden piers and an early twentieth-century carousel. Its one museum, at the Life-Saving Station, covers shipwrecks and lifeguards. That makes for an hour or two, not a reason to come.

Chicago offers more choice and keeps going later, with many bars licensed until 4am. Each neighbourhood has its own scene: cocktail and dive bars in Wicker Park and Logan Square, clubs in River North, Northalsted for gay nightlife, and dance nights rooted in the city's house-music history. It runs all year, moving into old taverns when winter comes.

Ocean City's nightlife is seasonal and simple. In summer there are sand-floored bayside bars at sunset and dance bars along the Coastal Highway, with a young, loud crowd until 2am. From autumn to late spring most of it goes quiet.

Both are flat, and neither has much in the way of wild country, but the outdoors works differently in each. Chicago's is parkland. The long lakefront path is ideal for cycling or running past harbours and the skyline, Lincoln and Jackson Parks offer birding on a migration route, and Indiana Dunes and Starved Rock are an hour or more away.

Ocean City's outdoors is water and marsh. You can paddle the back bays, go crabbing, take a fishing boat offshore after marlin, or see Assateague's wild ponies grazing among the dunes and pines.

Neither is a great base for excursions, but the outings are of different kinds. From Chicago you can take a train to Milwaukee, a real city with an art museum and breweries, or go out to Oak Park's Wright houses. Lake Geneva and the Michigan shore need a car.

From Ocean City, everything means driving around the Delmarva Peninsula's small towns: historic Berlin, the pony village of Chincoteague, Lewes with its ferry across to Victorian Cape May, or the Chesapeake waterfronts of St Michaels at the far edge of a day.

Both work very well with children, in opposite ways. Chicago offers indoor days: the coal mine and U-boat at the Museum of Science and Industry, dinosaurs, belugas and the planetarium side by side on the Museum Campus, plus a free lakeside zoo. That makes it a good choice outside summer too.

Ocean City is the classic seaside vacation: lifeguarded sand, boardwalk rides, water parks, go-karts and mini-golf, with condos that make a long stay easy. It is a summer-only formula, though, and early June belongs to graduating teenagers.

Chicago is far easier without a car. The L runs from both airports into the Loop, and the flat downtown grid puts the main museums and parks within walking distance of each other. Crossing between neighbourhoods often means a bus, but you can always manage without driving.

Ocean City effectively requires a car. There is no train, the busy Coastal Highway splits the strip and is unpleasant to walk beside, and the summer bus and boardwalk tram only help if you stay close to the sea. Assateague and every mainland town need a car.

Chicago is a real shopping city. The Magnificent Mile has flagships and vertical malls, there are luxury labels on Oak Street, and the old Marshall Field's store on State Street is worth seeing for its Tiffany ceiling alone. Wicker Park and Andersonville add independent, vintage and design shops.

Ocean City's shopping is boardwalk browsing: T-shirts, surf gear, taffy and fudge. For mainstream brands there is an outlet centre across the bridge.

Neither is cheap, but Ocean City is easier on a moderate budget. Sharing a condo among a group, staying in an older motel a few blocks back from the sea, eating boardwalk food and spending free days on the beach all keep costs down. Coming in late May or September cuts room rates sharply.

Chicago's downtown hotels, heavy taxes and sit-down dinners add up faster. To save, eat at taquerias and hot dog stands, travel on the L, and fill days with the free lakefront, Millennium Park and the zoo.

In Chicago, performance is a reason to plan the whole trip. There is a world-class symphony on Michigan Avenue, a full opera season, the Goodman and Steppenwolf alongside dozens of storefront companies, nightly improv at Second City, and electric blues and late jazz sets in clubs across the city.

Ocean City offers seaside-resort entertainment in the summer season: touring comedians and tribute bands at the convention centre, free shows at the boardwalk bandstand, and cover bands in the bars.

Chicago's best way to unwind is to sweat it out. Its century-old Russian-and-Turkish bathhouse in Wicker Park and a Korean-style bathhouse in the northern suburbs offer real heat and cold plunges. The warm conservatory glasshouses in Lincoln Park and Garfield Park give you a quiet break from the city, even in midwinter.

Ocean City has a few day spas and no bathing tradition, and in summer it is noisy. Its calm comes from an empty beach at dawn in the northern condo stretches, out of peak season.