Montevideo or Buenos Aires?

Buenos Aires faces the Río de la Plata but has no beach at all. The Costanera has grassy riverside promenades for sunbathing, but the water is too silty and polluted for swimming. To swim you need a hotel or club pool, or a separate stay on the Atlantic coast at Mar del Plata.

Montevideo is the only one of the two where a beach afternoon is part of city life. Sandy beaches run along the Rambla from Ramírez and Pocitos to the wider, quieter sands of Carrasco. The water is the same brownish estuary, though, and swimming is sometimes advised against after heavy rain.

Both cities put beef grilled over wood embers at the centre of the table, but Buenos Aires has more around it. There is an Italian strand of thick pizza, fresh pasta and excellent ice cream, and grand coffee houses such as Café Tortoni. Palermo has ambitious modern kitchens and wine bars, and Mendoza Malbec comes with all of it.

Montevideo's signature meal is a session at the smoking grills of the Mercado del Puerto with a glass of medio y medio, along with the chivito and Tannat from nearby wineries. It satisfies for a few days, but there is little street food and fewer kinds of kitchen to rotate through.

Buenos Aires gives you more to see, and on a bigger scale. You can walk from the Casa Rosada along Avenida de Mayo to Congress and lose an hour among the mausoleums of Recoleta Cemetery. The Bellas Artes and MALBA are two serious art collections, and San Telmo and La Boca add older streets.

Montevideo's sights fit into the Ciudad Vieja and Avenida 18 de Julio. The highlights are the Palacio Salvo, the Torres García museum and the museum of the 1972 Andes crash. Two or three days cover it, and parts of the old town look neglected.

This is one of the widest gaps between the two. Buenos Aires has a full nightlife scene: cocktail bars behind unmarked doors and rooftop terraces in Palermo Soho and Hollywood, electronic clubs that run past dawn, scruffier bars in San Telmo, and milongas into the small hours. Even weeknights have life.

Montevideo keeps the same late hours on a smaller scale. There are friendly bars in Pocitos, Punta Carretas and the Ciudad Vieja and a student crowd in Cordón, but weeknights are quiet, and in summer much of the party crowd heads to the coast.

Neither city has hills or wild country nearby, so the outdoors means parks and water in both. Buenos Aires has the jogging and cycling loops of the Bosques de Palermo and the wetland birdlife of the Costanera Sur reserve. About an hour north are the brown channels of the Paraná Delta, which you can explore by kayak or launch.

Montevideo's strength is the long waterfront Rambla, made for evening walks, cycling and sunsets, with kitesurfing on windy days. The low Cerro gives a view back over the bay, and gentle walks in the sierras near Minas are about an hour and a half away.

Both cities send you to Colonia del Sacramento, but the journey differs. From Buenos Aires a fast ferry crosses the river in a little over an hour, while from Montevideo it is about two and a half hours by bus. Buenos Aires also has inland outings to Tigre and the delta, the gaucho town of San Antonio de Areco, the basilica at Luján and the planned city of La Plata.

Montevideo looks along the coast instead, to old-fashioned Piriápolis and to Punta del Este with Casapueblo nearby. The Tannat wineries of Canelones are less than an hour away.

Late dinners with children in tow are normal on both shores, so what separates them is the kind of day out. Buenos Aires has more attractions built for children: the planetarium and pedal boats among the Palermo lakes, the Museo de los Niños in Abasto for a rainy afternoon, and the Temaikèn biopark about an hour north. Getting to them takes effort, though, because of the long distances, heavy traffic and broken pavements.

Montevideo has no major aquarium, science museum or theme park, but its days are simpler to run. Children can scoot and cycle along the Rambla, paddle in the shallow, calm water of the city beaches in summer and go on the rides at the small old-fashioned amusement park in Parque Rodó. Distances are moderate, so families spend less time in taxis.

Buenos Aires is easier to cover because of the Subte, which links the centre with Palermo. The colectivo buses run day and night, and one card works on both. The catch is size: San Telmo, Recoleta and Palermo are each a long walk from the next, and La Boca is not on the metro.

Montevideo has no metro or tram, so you rely on buses, which are slow at busy times, or on taxis. The old town and 18 de Julio are easy on foot, and the Rambla makes walking or cycling between the coastal districts pleasant, but the city stretches a long way along the shore.

Buenos Aires is the place for a proper shopping trip. You can buy leather jackets and bags around Villa Crespo, browse independent designers in Palermo Soho and visit the upmarket boutiques of Avenida Alvear and the painted domes of Galerías Pacífico. On Sundays the Defensa fair in San Telmo runs for blocks of antiques.

Montevideo's shopping is mostly crafts: knitwear, leather, silver-trimmed mate cups and gaucho knives. The Sunday Tristán Narvaja market is the one outing worth planning, and beyond that it is malls.

Buenos Aires usually makes a budget go further. Transport is very cheap, neighbourhood parrillas and pizzerias serve generous portions, and good wine costs little. Palermo and Puerto Madero charge European prices, though, and the currency's long history of swings makes costs hard to predict.

Montevideo costs about what Southern Europe does for restaurants and hotels, and hotels in Pocitos and Punta Carretas are priced like a European capital in summer. Cheap buses, free museums and set lunch menus help, but it is not a budget city.

Buenos Aires has the bigger stage. The Teatro Colón is one of the world's great houses for opera, ballet and symphony. The playhouses of Avenida Corrientes and a large independent theatre scene add plenty more, and tango is at its fullest in neighbourhood milongas with live orchestras.

Montevideo is smaller but has Carnaval, a tradition Buenos Aires cannot match. It lasts more than a month, with murga choral satire on neighbourhood stages and candombe drumming in Barrio Sur and the city's own Palermo district. The Teatro Solís and the SODRE carry the opera and ballet, though the programme thins outside summer.

In Buenos Aires you have to find the calm at the right hour. The sobremesa, the long talk at the table after a meal, can quietly fill an afternoon, and on Sunday mornings the avenues empty and fall silent. For massages there are hotel and day spas in Palermo and Recoleta, and Argentina's thermal springs are provinces away.\n\nMontevideo is the more restful stay because its calm needs no timing. Even the centre feels unpressured on an ordinary weekday, and the city asks little of you from morning to night. Treatments are again limited to upmarket hotels, and Uruguay's hot springs lie too far north for a day out.