East Italy is a coast of passage with few anchorages, but fine food. South of Vieste, ports are fairly widely spaced. Going north, Venice is a "must see". There's good value and popular (if cold and windy) on-shore wintering at Monfalcone near Trieste. Many who cruise Croatia winter there.
This page describes the Adriatic in general, and leads to more detailed pages about each cruising region. The sea is 420nm long and 100nm wide. The high spot is cruising Croatia, which should not be missed. There is a marked difference between the high standards of food and service in Italy, compared with the more simple standards along the eastern shores. There's more unsettled weather in the Adriatic than in other parts of the Mediterranean - with winter frosts in the north.
Sicily, Malta and S Italy are normally visited in transit between the eastern and western Mediterranean. Take it slow through Sicily, though. Aim to spend at least two weeks cruising the north and east coasts to see the volcanoes and ancient sites. Include the Aeolian islands, crowded in high season, but not to be missed. Marinas in S Sicily offer wintering bargains.
Malta (EU) provides excellent wintering and yacht service facilities, and nearby Tunisia (outside EU) is good value for wintering and fuelling.
The 600nm coast of Italy rom the French border to the toe spans a range of cultures; from the monied and smart Riviera, through historic Tuscany, past wealthy Roma and scruffy Napoli, to the relative poverty of Calabria. The list of inland 'must visit' places is long, including Florence, Siena, Pisa, Roma, and Napoli. Add Pompeii, the crater of Vesuvius and Herculaneum to the list.
Stir in the long string of small offshore islands (from Elba to Capri). Season with Italian food, and it's easy to see why many motor cruisers choose to cruise this coast, crowding it in peak season (Mid July to late August). Marina costs vary widely, but most are expensive; €100 per night for 12m is common. There are enough anchorages to keep overall mooring costs low. Rather light summer winds are a drawback for sailboats. Live-aboards have wintered near Roma.
The whole of Sardinia provides good cruising, with miles of pristine white beaches. North Sardinia is the most popular area, rich with anchorages, while South Sardinia is useful for cruisers travelling east or west through the Mediterranean. The western and eastern coasts have their attractions but are largely seen as a means of travel from N to S. They offer quiet cruising, especially on the east side, with few other yachts. Alghero and Cagliari are good destinations and good wintering spots.