The parking arrangement is fine, but completely baffling on arrival. I wasted quite a bit of time trying to figure out what to do. It might be useful to tell people coming by car more precisely where to go, although this might not always work, given Arezzo's complex street pattern.
Unbelievably friendly staff--both women who were at the desk during my stay were amazingly warm and helpful. They explained the rather complicated parking situation to me, pointed out some sights I had not been aware of, offered me a coffee before my departure, overall made me feel very looked after.
Also, the location is great, easy walking distance from all the sights.