I booked a car asking to pick it up at St Julian and bring it over to the airport.
When I arrived, the person told me I had to pay an extra €21ex-VAT for me to drop it at the airport. This fee was not in the quote and the person told me it was a new fee implemented this year. As I was stuck with them (go and hire a car on a Saturday morning in peak season), I took the car.
I called AVIS afterwards three time to make a claim only to hear on the third time that if I didnt like the conditions, I should not accept the terms at the agency and not take the car. They did not want to listen to the fact that this was never in the quote I got.
This is unfortunately not the first time I am having issues with Avis - last year in Greece the local agency in Patmos never got my request for rental (while I had received a confirmation in writting).
Just avoid them.