Da Nang or Sapa?

This is the biggest difference between the two. Da Nang has one long sandy beach running from the Son Tra peninsula past the Marble Mountains, with warm water for much of the year. The quieter An Bang is just down the coast near Hoi An.

Sapa is in the mountains and has no coast at all, and its streams are too cold and shallow to swim in. If you want sea time as well as the terraces, you will need a separate stretch of your trip on the coast, and Da Nang is one of the natural places for it.

Da Nang has the deeper food culture. You can eat spicy central Vietnamese dishes such as mi quang and banh xeo, fill up in the food halls at Han and Con markets, and pick seafood from tanks on the beach road to have it grilled to order. The strong iced coffee is good too.

Sapa's cooking is mountain food: salmon and sturgeon hotpots, evening grills by the lake and Hmong dishes such as thang co, with corn wine to drink. It is very welcome after a long day's walking, but the range is narrow and most of the centre is generic travellers' cafés.

Neither is a great sightseeing city, but Da Nang gives you more to visit. It has the Museum of Cham Sculpture, the cave shrines of the Marble Mountains and the pink French-era cathedral, and two days covers them well.

Sapa's town has only its stone church and a small museum. Its culture is in the Black Hmong, Red Dao, Tay and Giay villages, which you meet on foot. That makes it a living culture you walk through rather than buildings you tour, and it feels more authentic the further you go from town.

Da Nang has much more to do after dark. There are rooftop bars along the Han River, open-air beer halls full of locals, a dense block of bars in An Thuong behind the beach and a few loud clubs at weekends.

In Sapa an evening means hotpot by a fire, a drink in one of the few travellers' bars and an early night before the next walk. There is no club scene.

Both have impressive scenery, but Sapa is built around it. The Muong Hoa valley's terraces, trails from town to the villages, waterfalls on the Tram Ton Pass and the 3,143m summit of Fansipan make it one of Vietnam's great walking areas.

Da Nang's nature is more varied but less immersive. It has the langurs and viewpoints of Son Tra, the ride over the Hai Van Pass, rainforest at Bach Ma, snorkelling off the Cham Islands and surf in the cooler months. The heat and the autumn rain cut down the hiking, though.

Da Nang is the stronger base for day trips. Hoi An's lantern-lit old town is under an hour away, the Cham temple ruins of My Son are an easy outing, and the imperial citadel and tombs of Hue make a long but rich day over the Hai Van Pass.

From Sapa the standout trip is the Sunday market at Bac Ha, plus a few smaller hill markets. Almost everything else means going deeper into the mountains rather than to a different place.

Da Nang suits most families. It has a wide beach, resort pools and kids' clubs, the cable car and indoor amusement park at Ba Na Hills, water parks, and a culture that makes a fuss of children. The things to watch are crossing streets through motorbike traffic and the rainy autumn.

Sapa works for older children who can manage short treks and would enjoy a valley homestay and the Fansipan cable car. With toddlers it is hard going: steep, uneven streets, muddy trails, cold rooms in winter, persistent vendors and almost nothing made for children.

Neither has useful public transport. In Da Nang, cheap app-booked cars and motorbike taxis cover the short, flat distances between the river, the beach and Hoi An easily.

Sapa's centre is small enough to walk but steep. Beyond it you trek, hire a car with a driver or ride pillion on a motorbike. Getting there from Hanoi also takes most of a day by road, or a night train followed by a drive up the mountain.

Da Nang's shopping is everyday and practical. Han and Con markets sell coffee, dried seafood and fabric, the Non Nuoc workshops carve stone of every size, and there are modern malls for chains and supermarkets. For made-to-measure clothes, most visitors go to the tailors of Hoi An, close by.

Sapa sells almost nothing but handicrafts: Hmong and Dao embroidery, indigo cloth, brocade bags and silver. Some of it is fine handwork, but machine-made copies are common and sellers can be pushy. Bac Ha market is the best place to find the real thing.

Both are very cheap, so the difference is where the money goes. In Da Nang, street food, app taxis and massages cost very little, and the expense comes with beachfront resorts and Ba Na Hills.

In Sapa, guesthouses, homestays and guided treks are inexpensive. Central hotels charge a bit more than in the lowlands, and the Fansipan cable car is the one big cost.

Da Nang has a short programme of shows. It keeps tuong classical theatre alive, with painted faces and drums, though performances are irregular. Cover bands play in the bars near the beach, and the summer fireworks festival lights up the Han River. Near Hoi An there are large staged shows on the river and evening bai choi singing games.

Sapa has no theatre or concerts at all. The only performances are short sets of Hmong and Dao pan-pipe music and dance in the square on weekend evenings, and the odd staged show in a village.

Da Nang is easier for a relaxing break. There are massage parlours on nearly every beach street, resort spas on Son Tra with treatment villas over the sea, and a hot springs park about 30km out. Early swims and long coffees set an easy pace.

Sapa has the Red Dao herbal bath, a real bathing tradition and a wonderful soak after a trek. For proper calm, though, you need a homestay out in the valleys rather than a room in the busy town.