I had a bad experience renting car in Tasmania with Avis.
I went there in Dec last year and everything seems to be perfect until we returned to HK. Avis sent us a letter stating that it will bill us A$1200 for damaging its car. The car we returned was in perfect condition and without having a staff to inspect the car but just a key drop counter, Avis just said whatever they like.
After sending several emails to Avis and Tourisim board in Tasmania. Avis finally agreed to cancel the charge but we were very irritated already.