I would rate it 70 out of 100.

Very good

Even though I had informed them that I bought full insurance through Zuzuche, the rental company desk still insisted on recommending their own full insurance.

Initially, it was agreed to return the car with a full tank. However, upon arrival, they required an empty tank and charged 67 euros for fuel. The staff was inefficient and kept chatting, taking an hour to complete a single process.

Despite booking over a week previously so that Avis would have plenty of time to set things up, when we arrived they did not have our car ready (Merc E Class) and did not have anything comparable to offer. After calling their associates, the only available alternatives were a monstrous Merc G Wagon (imagine trying to park that in the land of the Fiat 500) for more money, or a BMW 3 Series Touring. We took the BMW. Then we were informed that the insurance that we'd already paid for via Easyrentcars would not offer adequate cover, and for fully comprehensive cover we had to book with Avis. Given that we'd already had a car damaged in a car park in Italy on a previous trip, we felt that we had no option but to comply with Avis' advice.