I made a vid to show what Rio Cannas is like
Super smooth water-washed granite on most of the boulders which are like giant eggs, quite unusual and interesting climbing. As a place, though, Serra Oseli is nicer. In the vid at 2:14 you can here the motorbikes tearing up the SS125 and the mats felt useful walking back up the road in case one of these blokes lost it on the bend as they raced back to Cagliari...
Peter