Huatulco or San Miguel de Allende?

This is the widest gap between the two. Huatulco's bays offer something for each kind of beach day: town beaches at Santa Cruz and Chahué, resort sand at Tangolunda, gentle coral snorkelling at La Entrega, and wilder coves such as Cacaluta that you reach by boat or forest path. The water stays warm all year.

San Miguel de Allende has nothing to set against this. It lies on the central plateau, so swimming means a hotel pool or a soak in the spring-fed pools out in the countryside. Sea time there has to be planned as a separate leg of the trip.

San Miguel de Allende eats better and with more range. It has rooftop terraces facing the Parroquia, courtyard restaurants in colonial houses and chefs working with Bajío ingredients such as nopal and mesquite. At the cheaper end there are the Mercado Ignacio Ramírez and the evening taco carts, and much of the wine comes from Guanajuato's own high-desert vineyards.

Huatulco has its own pleasures: Oaxacan mole and tlayudas, whole fish grilled at beach palapas, and breakfast at La Crucecita's market. Serious restaurants are few, though, and international buffets make up much of the dining in Tangolunda.

In San Miguel de Allende the town itself is the sight. Its UNESCO-listed grid of cobbled streets and carved doorways leads from the pink spires of the Parroquia to San Felipe Neri, the Casa de Allende and the convent of Bellas Artes. Two unhurried days do it justice, though there are no major museums.

Huatulco was planned as a resort and has little history to show: the painted dome of La Crucecita's church, the small pre-Hispanic site at Copalita and the quiet colonial church in Santa María Huatulco.

Neither is a party town, but San Miguel de Allende has more going on in the evening. There are rooftop drinks as the Parroquia lights up, then mezcal bars and cantinas around the Jardín, and on Friday and Saturday the centre stays busy late, when weekend visitors arrive from Mexico City and Querétaro.

In Huatulco a night out usually means dinner and mezcal on La Crucecita's plaza or a drink at a beach bar by the Santa Cruz marina. Anyone who wants proper dancing goes up the coast to Zipolite.

Huatulco is the stronger choice for the outdoors. Its national park runs from dry tropical forest down to cliffs and coral, with snorkelling and diving, humpback whales offshore from December to March, and turtles nesting nearby. Inland, the Copalita River adds rafting, and the Sierra Sur foothills have waterfalls and coffee farms.

San Miguel's outdoors is gentler and drier. There are cactus trails and canyon views at El Charco del Ingenio, horse riding on ranches, mountain biking and dawn balloon flights over the Bajío, but these work best as a morning out rather than the focus of a trip.

San Miguel de Allende is much the better base for exploring. Guanajuato and Querétaro are each about an hour away, and the murals of Atotonilco are closer still. Dolores Hidalgo, Mineral de Pozos, Bernal and the wine country add enough for a week of outings, though the smaller places need a car or a driver.

From Huatulco, the outings mostly run along one stretch of coast: Mazunte's turtle centre, Puerto Ángel and Zipolite about an hour west, or the surf town of Puerto Escondido at two hours. Oaxaca city is too far to get there and back in a day.

Huatulco suits children better because the beach does most of the work. There is calm water at La Entrega and Santa Cruz, with fish to spot close to shore, and the Tangolunda resorts have pools and kids' clubs. With no zoo, aquarium or theme park, older children may tire of it after a week.

San Miguel de Allende is an adult town, and its steep, uneven cobbles make pushchairs a struggle. Still, the evening Jardín with its balloon sellers, the warm spring pools and the fiesta fireworks will keep older children happy for a few days.

San Miguel de Allende is easier to manage on foot, since everything a visitor wants is within a walk of the Jardín. The steep stone streets at about 1,900m take real effort, though, and arrival means a shuttle from Querétaro or León.

Huatulco is spread over several bays. Apart from compact La Crucecita and the easy walk down to Santa Cruz, you depend on taxis or colectivos, with boats or a hire car for the remoter coves. Distances are short, but you will spend most of your time riding rather than walking.

San Miguel de Allende is a real place to shop for crafts and décor. The Mercado de Artesanías has punched tin, blown glass and silver, the design shops sell high-quality folk art and furniture, and the former textile mill is full of artists' studios and antique dealers.

Huatulco's stalls around La Crucecita and Santa Cruz sell Oaxacan textiles, black pottery, alebrijes and mezcal among the beach souvenirs, which is enough for a few gifts. Neither town has fashion or department stores.

Huatulco is the cheaper of the two. Guesthouses in La Crucecita, market meals and short taxi rides keep a stay modest. Costs rise mainly at the all-inclusive resorts of Tangolunda, on boat tours and in high season.

San Miguel de Allende costs more, chiefly for a bed and dinner in the centre. Many rooms are in boutique hotels inside colonial houses, and the restaurants around the Jardín are priced for foreign residents and weekend visitors from the capital. A few streets away, street food, market lunches and cantinas stay cheap, and the churches and lanes that make up the town's main attraction cost nothing to see.

San Miguel de Allende has a real musical life for a small town. It has the nineteenth-century Teatro Ángela Peralta, chamber music and jazz festivals in their seasons, mariachi bands on the Jardín every evening, and street music and dance at the Alborada and in Holy Week.

Huatulco offers little beyond Oaxacan folk dance shows at the resorts, the odd bar band, and music on La Crucecita's plaza during festivals.

Both are slow places, but San Miguel de Allende offers more ways to enjoy that slowness. There are the hot mineral springs and domed grottoes towards Atotonilco, yoga classes and day spas serving the large resident community, and courtyards and rooftops made for idling in the dry, mild air.

In Huatulco the rest comes from the sea and the quiet, low-rise bays. The Tangolunda and Conejos resorts have full spas, and the temazcal steam bath is the traditional ritual, but there are no thermal waters and fewer yoga retreats.