Dusseldorf or Heidelberg?

Neither city is a place for a beach vacation, and neither river is safe to swim in. Düsseldorf has the slight edge because Unterbacher See, a lake with lawns and bathing areas, lies within the city boundary.

Heidelberg's swimmers use its outdoor pools or drive about half an hour to gravel-pit lakes on the Rhine plain. In both cases the sea is a long journey away, so plan any time by the water elsewhere.

Düsseldorf gives you more to eat. Alongside the Altstadt brewhouses with sauerbraten, Halve Hahn and the city's sharp mustard, it has one of Europe's largest Japanese communities, so ramen, izakaya and Japanese bakeries make a genuine second cuisine, and Carlsplatz market adds snacks and produce.

Heidelberg's kitchen is hearty Baden and Kurpfalz cooking, from Maultaschen to spring asparagus, and its real strength is wine from the Bergstrasse and Palatinate villages close by. Choose carefully, though, as the places on the Hauptstrasse aimed at day-trippers are uneven and the better meals are in side streets, in Neuenheim or in village taverns.

These two are evenly matched but offer very different things. Düsseldorf is a city of art collections: K20 with its Klee holdings, K21 with the net slung under its dome, the Kunstpalast and galleries shaped by the art academy. Its old town is largely rebuilt, so Benrath Palace and the Gehry buildings in the Medienhafen do most of the architectural work.

Heidelberg is the opposite case, with less art and far more old fabric. The red sandstone castle ruin, the Old Bridge, a baroque Altstadt and Germany's oldest university with its graffiti-covered Student Prison make a compact, photogenic set that suits anyone who wants historic streets more than galleries.

Düsseldorf is the livelier night out by a wide margin. Hundreds of pubs and brewhouses packed into the Altstadt spill onto the lanes at weekends, there are calmer cocktail bars in Carlstadt and the Medienhafen, and Carnival turns the whole city into a party for days.

Heidelberg's evenings centre on the Untere Strasse and a few historic student taverns with carved tables. They are fun in term time, but the town goes quiet early otherwise, and locals wanting a real club night head to Mannheim or Frankfurt.

Heidelberg has the better outdoors because the Odenwald forest starts right at the edge of town. You can climb the Philosophers' Walk for the castle view, ride the funicular up the Königstuhl at 568m, or explore the Celtic ramparts on the Heiligenberg, with the Neckar cycle path and the Palatinate Forest further out.

Düsseldorf's green space is flatter and gentler: Rhine meadows with long cycle paths to Kaiserswerth, Grafenberg forest and the Neandertal valley. It is pleasant for a stroll or a ride, but it can't offer forest walks straight from the old town.

Both are excellent bases, so the choice comes down to which region you want to see. From Düsseldorf, Cologne cathedral is under half an hour away, with Bonn, the Brühl palaces, the Ruhr's industrial heritage at Zollverein, Aachen and Dutch Maastricht all easy by fast trains.

Heidelberg looks towards the Upper Rhine and its Romanesque and medieval sites: Speyer's cathedral, Schwetzingen's gardens, Worms, Lorsch and Maulbronn. It also has gentler outings to castle villages up the Neckar and the wine villages of the Palatinate, although some of these are easier by car.

Düsseldorf's flat, compact centre and trams that take buggies without fuss make it the easier place to push a pram, and most of its treats are in town: the aquarium and natural history displays of the Aquazoo Löbbecke Museum, the tilted windows high up the Rheinturm, and wild boar and deer coming close in the free Grafenberg game park. Phantasialand and Movie Park Germany are each about an hour away.

Heidelberg's cobbled, sloping Altstadt is harder going with a pushchair, but its outings feel more like adventures. The funicular climbs to the Königstuhl and its small fairy-tale park, the compact zoo sits by the Neckar, and boat trips run upriver past castles. Within half an hour, the Technik Museum Speyer lets children climb into a space shuttle and a submarine.

Both are easy to manage without a car, but Düsseldorf is a little smoother. Its centre is compact and flat, the main districts are all within walking distance, and the airport is only minutes away by train.

Heidelberg's sights line up neatly along the pedestrianised Hauptstrasse, but the station is a tram ride west of the old town and the castle approach is steep and cobbled, which the funicular helps with. Both cities belong to large regional fare networks, Rhine-Ruhr and Rhine-Neckar, which make day trips simple.

Düsseldorf is the shopping city of the two, thanks to the Königsallee, where luxury flagships and jewellers line the canal. Department stores on Schadowstrasse, design shops in Flingern and stationery and homeware in the Japanese quarter add variety.

Heidelberg's Hauptstrasse is long, but it moves from chain stores to souvenirs, cuckoo clocks and beer steins. Apart from a few bookshops and boutiques in the side lanes, the best buys there are Bergstrasse wine and Studentenkuss chocolates.

Costs are much the same, and in both cities the hotel is the expensive part. Düsseldorf's room rates jump during its trade fairs, while Heidelberg's limited supply of rooms fills up with congresses, graduations and summer weekends, so many visitors stay in Mannheim instead.

Eating out is reasonable in both: brewhouse meals and noodle bars in Düsseldorf, and student cafés and simple taverns in Heidelberg.

Düsseldorf has more on stage. The Deutsche Oper am Rhein stages opera and ballet, the Tonhalle is home to a symphony orchestra in a former planetarium, and the Schauspielhaus is a leading theatre. On top of that come political cabaret, small jazz venues and the city's place in electronic music history as the birthplace of Kraftwerk.

Heidelberg makes up in setting what it lacks in scale. Its municipal theatre and philharmonic play through the season, the Heidelberger Frühling brings chamber music in spring, and summer plays and concerts are staged in the castle courtyard. For bigger opera productions, people take the short train ride to Mannheim.

Neither town has thermal springs of its own, and both rely on nearby spas. From Düsseldorf you can reach large thermal complexes and Aachen's hot springs, and its public pools have the mixed, swimwear-free saunas that are standard in Germany.

Heidelberg is within reach of the saline pools of the Kraichgau and of Baden-Baden. The way you relax differs too: in Düsseldorf it means walks along the Rhine and the Japanese garden in Nordpark, while in Heidelberg it means forest paths and slow evenings in wine taverns.