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.

Very, very dissatisfied.

The car we booked wasn't available, so they upgraded us to a Volvo V60. Although the rental cost increased a bit, it was still worth it.

AVIS and Budget share the same counter. There were quite a few people picking up cars at Rome airport, and I waited for almost an hour. The car was in good condition, and returning it was even easier. Since the fuel was used up, the return desk just took the keys and signed off, and we were good to go. Very convenient.

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.