Marco Island or Miami Beach?

Both beaches are wide and pale with calm water, but they feel very different. Marco Island's curve of Gulf sand is quiet and shallow, good for shelling, wading out on the Tigertail sandbar and watching the sunset over the sea. Keewaydin's undeveloped shore is a short boat ride away.

Miami Beach has the edge overall. It runs for about 11km along the Atlantic, with lifeguards and a beachwalk, and its water stays warm enough for proper swimming through the winter. You can choose busy South Beach or the calmer stretches of Mid-Beach and North Beach. In return, the busy parts come with crowds, music and the occasional summer seaweed.

Marco Island's food is mostly Gulf seafood: grouper sandwiches, shrimp and stone crab claws, eaten on waterfront decks or at the dockside shacks of Goodland. Beyond that the choice is narrow, so for a more ambitious dinner you drive to Naples.

Miami Beach eats far better and with much more variety. Its Latin American cooking brings croquetas, cafecito, arepas and ceviche alongside upscale hotel and chef-led restaurants. The trick is to avoid the tourist menus on Ocean Drive and eat on the side streets, in North Beach or across the causeway in Little Havana.

Marco Island has little to see. It is a resort town built within living memory, so most of it is canals and condominiums. The one real cultural stop is the historical museum, which tells the story of the Calusa people and the carved wooden figures dug up here in the 1890s, along with the island's clam-cannery past. Beyond that there is only the old fishing village of Goodland.

Miami Beach has a sight of its own in the Art Deco Historic District. Its hundreds of pastel hotels and apartment blocks from the 1930s have porthole windows and neon, and you can see them on an easy walk. The Wolfsonian, the Bass and the Holocaust Memorial are enough for another day or two. The bigger museums are across the bay on the mainland, but even without them Marco Island has nothing to match it.

This is the biggest gap between the two. On Marco Island the evening means a sunset drink and dinner, maybe a resort lounge afterwards, and the island is quiet well before midnight.

South Beach is the opposite: clubs with guest DJs until dawn, pool parties in the afternoon and lobby bars where people go to be seen, with dress codes and door policies to match. For something gentler, the cocktail bars of Sunset Harbour are still far livelier than anything on Marco Island.

Marco Island is the better base for wildlife. It sits on the edge of the Ten Thousand Islands, so you can kayak through mangroves, see manatees and dolphins, fish some of Florida's best inshore waters, and reach Rookery Bay, Big Cypress and the Fakahatchee Strand within an hour.

Miami Beach is a built-up island, and its nature is mostly at sea: snorkelling and diving on offshore reefs and wrecks, and Biscayne National Park's keys. Oleta River State Park offers mangrove paddling closer to the city. Neither has hills, and summer heat drives everyone outdoors early in both.

From Marco Island the outings are pleasant but limited. Naples has its pier and gallery streets, Everglades City and Chokoloskee have their old trading post, and further north are the Edison and Ford Winter Estates and the shelling islands of Sanibel and Captiva.

Miami Beach has a stronger list, starting just across the bay with Little Havana, the Wynwood murals, Vizcaya and Coral Gables. Further away you can reach Fort Lauderdale, Palm Beach and Key Largo in a day. For both, you will need a car or a tour.

For children the two work about equally well, but in different ways. Marco Island is the gentler of the two: shallow, still water, soft sand, lagoon wading and resort kids' clubs, on an island that is quiet the whole time.

Miami Beach adds lifeguards along the whole shore and playgrounds behind the sand. The catch is that South Beach is loud on weekends and during spring break, so families are better off in Mid-Beach or near Surfside. In both places the zoos and children's museums are on the mainland.

On Marco Island you can cycle between the beach and the shops in the cooler months, but for anything else you need a car. That includes Naples, the airport and the Everglades.

Miami Beach is much easier. South Beach is compact enough to walk, and free trolleys and buses run up Collins Avenue, so a beach stay works without a car. Getting off the island is the weak point, with no rail link, buses that get stuck on the causeways and parking that is hard to find.

Shopping on Marco Island is limited to resort wear, shells and coastal décor in a few small plazas. Anyone serious about it drives to Fifth Avenue South in Naples.

Miami Beach has more to offer on the island itself. Lincoln Road, the pedestrian mall laid out by Morris Lapidus, is lined with chain stores and is nicer for an evening walk than for finding anything unusual. At the northern tip, Bal Harbour has a full set of European luxury houses.

Neither is cheap, and in both the winter peak is the most expensive time, with summer rates much lower. On Marco Island the costs are resort rooms, waterfront dining and a hire car you can hardly do without, while a weekly condo with a kitchen helps families and groups.

On Miami Beach the extras add up: resort fees, parking and South Beach cocktail and club prices. On the other hand, you don't need a car, the trolleys are free, Cuban takeaway windows are cheap and hotels on the side streets or in North Beach cost less.

On Marco Island the music is a guitarist in a resort bar or a show at the community theatre, and for the philharmonic you go to Naples in winter.

Miami Beach has a real arts scene of its own. The New World Symphony plays in its Frank Gehry hall and sometimes projects concerts onto the outside wall for people on the lawn. Miami City Ballet is based on the island, and the Jackie Gleason and Colony theatres host touring and smaller shows from autumn to spring.

Both rely on resort spas rather than any bathing tradition. The difference is the setting. On Marco Island the whole island is unhurried, so any hotel makes a calm base for a slow week.

Miami Beach's bigger resorts have more elaborate facilities, with hydrotherapy circuits, steam rooms and sunrise yoga on the sand. Rest depends on where you stay, though: South Beach is loud, so look in Mid-Beach or towards Surfside.