Avons do seem to wear down faster then most. Softer compound = great traction = shorter life span.
As already said. Certain models of Dunlops, as well as Michelin, and Metzelers are well spoken of here.
Bike and style of riding will cause your mileage to vary.
As already stated...my experiences with Avon's were they had great grip but just wore out to fast due to the softer compound. The Dunlop american elites seem to be a great tire. What I'm running. On my SG now