I'm heading over to Tasmania and renting a car from the Airport. From the list, Europcar seems to be the cheapest, but I've heard tons of problems about them, but back in July it was reported that Europcar Australia has revoked the franchise and is managing it themselves.
Has anyone had experience with them since? And have they cleaned up their act?
Not quite answering your question, but we just went to Hobart and used Hertz with the 20% off special; you can book now and pay when you arrive at the airport and we were very happy with their service. It's against the OzBargain spirit, but sometimes cheapest is not always best.
Also depending on the length of your stay, it might be cheaper to get travel insurance to cover the circa $3000 excess fees should the worst happen, rather than paying the Hertz excess reduction premium. Bear in mind that if you do have an accident using your own insurance you have to pay the $3000 to Hertz and claim it back from the travel insurance company, so make sure you get a Police report, etc.