The most important factors when purchasing Sardinian wine are the producer and the type of wine (white: Vermentino and red: Cannonau (another name for Grenache/Garnacha) and Carignano being the most important).
While some Sardinian wine can be very good, very little of it is age worthy, so there is no need to be concerned with vintages except to ensure that the wine is not past its prime.
Generally speaking the whites should be drunk within 2 years and the reds within 5 to 6 years of their vintage date.
Historically, Sardinian white wines had high alcohol content and low acidity. Modernized production methods have been successful in producing very enjoyable Vermentino white wines which are floral, have a normal alcohol level and good acidity. Vermentino white wines pair perfectly with local seafood dishes and are very affordable. The terroir (see below) does not seem to be any guarantee of quality so look primarily at the producer.
Producers to look for include: Argiolas, Capichera, Dettori, Mesa and Tenute Soletta
Vermentino di Gallura
Vernaccia di Oristano, Vermentino di Sardegna
Cannonau is Grenache in France or Garnacha from Spain, so can be similar to red wine from the Rhone. It can be a very enjoyable red wine. When at its best it will have a lot of fruit, with notes of black cherry and is medium bodied. It goes well with the meat courses of which there are many in Sardegna such as roast suckling pig (porcetto), lamb stew (ghisadu) and wild boar as well as with cheeses. I very much like the finer examples of this wine.
Producers to look for include: Giuseppe Gabbas, Giovanni Montisci and Tenute Soletta.
Cannonau di Sardegna
Carignano is often credited with being Sardegna’s best red wine (although it is also a table wine). Carignano is said to be similar to the Spanish Cariñena.
Producers to look for include: Agricola Punica, Argiolas, Barrua, Cantina Santadi, Mesa and Sardus Pater.
Carignano di Sulcis
There are also a number of passito-style sweet wines from Sardegna.