Barcelona or Zaragoza?

This is the widest gap between the two. Barcelona has a run of sandy, man-made beaches from Barceloneta to Mar Bella that are good for swimming from June to late September. There is more space at Sitges, Castelldefels and along the Maresme, all under an hour away by train. The city beaches are packed in high summer, but they are right there.

Zaragoza has no sea and no river swimming, since the Mediterranean is more than 200km away. In the summer heat the choice is a municipal open-air pool or a hotel pool, so if you want beach time you will need to add a few days on the coast.

Both cities eat late and well, but Barcelona has a much wider range. Catalan cooking, from suquet fish stew to calçots with romesco, comes alongside seafood rice by the sea, cava, the counters at Santa Caterina and Sant Antoni markets, and one of Europe's most serious tasting-menu scenes.

Zaragoza is narrower and more traditional. The pleasure is a bar-to-bar crawl through El Tubo, where each counter has its own speciality, along with hearty Aragonese dishes such as ternasco lamb and borage with clams, and generous reds from Cariñena and Somontano. Fine dining and international food are thin on the ground.

Barcelona has more to see, and more that exists nowhere else. The Sagrada Família, Casa Batlló, La Pedrera and Park Güell sit on top of a Gothic Quarter with Roman walls and Santa Maria del Mar, and the Picasso Museum and the MNAC's Romanesque frescoes add depth. A week of sightseeing is easy to fill.

Zaragoza packs a long history into a smaller space. The Aljafería palace, the Basílica del Pilar with its Goya ceilings, La Seo's Mudéjar wall and the underground remains of Roman Caesaraugusta reward two or three days. Beyond the old core the city is largely modern.

Barcelona's nights are bigger and more varied, and each district has its own scene: cocktail bars in medieval cellars in the Born, scruffy Raval bars, outdoor drinking in Gràcia's squares, the Eixample's gay scene and electronic club nights that go on until dawn, busy even midweek.

Zaragoza is friendly but smaller. The night moves from El Tubo's tapas to the bars around Plaza San Felipe and Plaza Santa Marta, full of students at weekends and quiet on ordinary weeknights. The exception is the Fiestas del Pilar in October, when the streets stay packed until dawn for a week and a half.

Barcelona has wild country on its doorstep. The wooded Collserola hills begin at the edge of Gràcia and Sarrià, the Carretera de les Aigües is a flat path with views over the whole city, and you can sail or paddleboard off Mar Bella. Montserrat's pinnacles and the Costa Brava's coastal paths are within easy range.

Zaragoza sits on dry steppe swept by the cierzo wind, so in town you are limited to the Ebro path and the big parks. The scenery further out needs a car: beech forests on the Moncayo, the red towers of the Mallos de Riglos and the badlands of the Bardenas Reales. That stark, desert-like landscape is something Barcelona does not have.

Both make good bases, and the difference is in how you travel. From Barcelona, fast and local trains reach Girona in under forty minutes, Tarragona's Roman amphitheatre, Sitges and Montserrat, so a week of outings needs no driving.

Zaragoza's great asset is its position on the high-speed line, with Madrid and Barcelona each about an hour and a half away. Its Aragonese outings, such as the castle at Loarre, Tarazona's Mudéjar cathedral, the ruins of Belchite and cliff-top Alquézar, are rural and much easier with a hired car.

Barcelona gives children more to do. There is the aquarium at the old port, the hands-on CosmoCaixa, the zoo in the Ciutadella and the funicular up to the Tibidabo funfair, with beaches a metro ride away and PortAventura about an hour south. The downsides are the crowds and the narrow old-town streets, which are hard going with a pushchair.

Zaragoza is calmer and easier to manage, with a flat centre, wide pedestrian squares, and the river aquarium and playgrounds at the old Expo site. Beyond that the list runs short, and there is no beach to fall back on in the hot summer months.

Both centres are flat and good for walking, but Barcelona's transport covers far more ground. It has a simple colour-coded metro, buses, trams and local trains on the same tickets, and bike lanes across the city. You will use it, since the Sagrada Família, Park Güell and Montjuïc are rides and climbs away from the old town.

Zaragoza is smaller. Most of its sights sit along one walkable stretch from the Pilar to the Aljafería, with a single tram line and buses filling the gaps. The rural sights are the hard part, since they are difficult to reach without a car.

Barcelona is clearly the better place to shop. The Passeig de Gràcia has luxury and Spanish fashion houses among Modernista façades, while the Born, Gràcia and the Raval add independent designers, craft shops, vintage clothes and records.

Zaragoza has the everyday Spanish high street along Paseo de la Independencia, a department store and a large mall on the southern edge, but little independent design. The best things to take home are local: candied frutas de Aragón, wine and ceramics from Muel.

Here Zaragoza comes out clearly ahead. Central hotels are good value for most of the year, sightseeing costs are modest and the Pilar basilica is free, so a few days there cost noticeably less. The exception is the October fiestas, when rooms fill up.

Barcelona costs more than most of Spain. Hotels are the main expense, and the tourist tax and steep entry fees at the Gaudí buildings add to it. Set lunches, market counters and transport passes help, but they narrow the gap rather than close it.

Barcelona has more on most nights. The Liceu has a full season of opera and ballet, concerts at the Palau de la Música Catalana take place under its stained-glass ceiling, and there are jazz cellars and flamenco stages, with Sónar and Primavera Sound filling the early summer.

Zaragoza's programme is reliable but provincial, built around touring orchestras at the Auditorio and plays at the nineteenth-century Teatro Principal. What it has that Barcelona does not is the jota, Aragon's leaping folk song and dance, seen at its best during the Fiestas del Pilar.

Neither city is a place for a spa trip. Both have only hotel spas and an Arab-style bath house or two, so the difference is in the kind of rest. In Barcelona you have to look for calm away from the crowded, late-night centre, on the Collserola paths or a Gràcia terrace, and a nearby seaside town is better still.

Zaragoza is quieter by nature, with long lunches, evening walks along the Ebro and shade in Parque Grande. The thermal waters of Alhama de Aragón are a little over an hour away, though the summer heat and the cierzo wind can take the edge off.