Kefalonia or Mykonos?

The beaches are equally strong, but they work in different ways. Kefalonia's are dramatic and spread out: the white pebble crescent of Myrtos under cliffs, quieter Petani and red-sand Xi on the Paliki peninsula, and long sand at Skala and Lourdas in the south. Choosing between them means a base on the right coast and drives along winding roads.

Mykonos packs its sandy bays along the south coast, close to Chora and linked by sea taxis. They are more organised and more social, from polished Psarou to the party beaches and roomier Elia and Kalafatis, while the north coast is often too windy in summer.

Neither island is a serious food destination, but they feed you differently. Kefalonia is family tavernas in harbour villages and hill villages, its own meat pie and garlic aliada with salt cod, and Robola tastings at the wineries of the Omala valley, though menus soon repeat.

On Mykonos the meal is often about the setting, grilled octopus at tables over the water in Little Venice. There is far more choice of sushi, fusion and chef-led dining, but it is aimed at being seen, and good, simple Greek cooking takes more seeking out, around Ano Mera's square for instance.

Mykonos has much more to see, thanks above all to Delos, the sacred island of Apollo, whose sprawling ruins and mosaic floors are a short boat ride away. Chora itself, with its windmills, Little Venice and the Paraportiani church, makes a full day of wandering.

Kefalonia lost most of its old towns in the 1953 earthquake, so its sights are scattered outings: pastel Fiskardo, the Venetian fortress at Assos, the Mycenaean tomb at Tzanata and the Agios Gerasimos monastery. Pleasant, but not a reason to choose the island.

This is where the two are furthest apart. From June to September Mykonos runs from beach-club afternoons through Chora's cocktail and dance bars, with its long-established gay scene, to big clubs that close at sunrise.

Kefalonia's evenings are long dinners and a drink by the harbour, with a modest bar strip at Lassi and a late summer crowd on Argostoli's Lithostroto. Anyone wanting to dance until morning will be disappointed there.

Kefalonia is by far the greener, wilder island. Mount Ainos rises to about 1,628m as a national park of dark Greek fir and semi-wild horses, the west coast falls in white cliffs, and under the ground lie the boat-borne lake of Melissani and the stalactites of Drogarati, with loggerhead turtles in Argostoli harbour.

Mykonos is low, brown and stony, beautiful for its light and sea rather than its scenery. Its outdoor strengths are the meltemi, which makes Korfos Bay and Kalafatis good for kitesurfing and windsurfing, and clear water for diving around reefs and wrecks.

Mykonos has the wider choice, all of it by boat across the Cyclades: Tinos with its pilgrimage church and marble villages, neoclassical Ermoupoli on Syros, and Paros and Naxos within about an hour on fast boats. The meltemi can cancel crossings, and every outing is another Cycladic island.

From Kefalonia the standout is Ithaca, a short ferry from Sami, with Vathy, Kioni and the sites linked to Odysseus. Summer boats reach northern Zakynthos and Lefkada, but beyond that the list is short and mostly seasonal.

Kefalonia is the easier family choice. The sandy, shelving beaches at Skala, Lourdas and Xi suit small children, the boat ride through Melissani and turtle spotting make good outings, and the evenings are quiet. The catch is long, hot drives and no attractions built for children.

Mykonos has shallow bays at Agios Stefanos, Ornos and Platis Gialos and a water park near Elia, but the island is shaped around adult nights out, and Chora is loud and packed late in high summer.

Mykonos is easier because it is small: nowhere is much more than half an hour from Chora, the town is car-free, buses serve the south-coast beaches and sea taxis hop between bays. Its weak points are a shortage of taxis and congested roads in July and August.

Kefalonia is large and mountainous, so a hired car is close to essential. The drive from Argostoli to Fiskardo takes about an hour and a half, buses are too infrequent to plan around, and parking at Myrtos and Assos is tight in summer.

Mykonos is the better place to shop, if what you want is a summer wardrobe. Matoyianni Street and the lanes around it hold designer resort wear, linen, Greek jewellery and galleries, open late into the evening.

Kefalonia offers everyday clothes and gifts on Argostoli's Lithostroto and a few craft stalls in Fiskardo. The best things to take home are edible: Robola wine, thyme honey and boxes of red mandoles.

Kefalonia costs much less. Taverna meals are reasonable and apartments around Skala, Lourdas and Lassi are fair value, with car hire the main extra and Fiskardo and Assos the pricier corners.

Mykonos in season is among the most expensive places to vacation in Europe, from hotel rooms to cocktails and sunbeds at the fashionable beaches. Staying inland, eating gyros and using buses helps, but it never becomes cheap in summer.

Neither island has a theatre or concert season, but Kefalonia has a musical tradition of its own: kantades serenades with guitar and mandolin and a philharmonic band heard at village festivals and summer concerts in Argostoli's squares. On Mykonos the music is mostly club and beach-bar DJ sets, with an occasional village festival as a lucky find.

Kefalonia is the more restful island, less for its spas than for its pace: long lunches in hill villages, slow harbour evenings in Assos and the quiet of the Paliki peninsula.

Mykonos has polished hotel spas with massages and sea-facing yoga, but its summer rhythm of beach clubs and late nights works against rest. Those wanting calm should stay near Agios Sostis, Ftelia or beyond Kalafatis.