Going by the few times I have needed to rent a car, I've found Sixt to be better than Hertz and Avis. Better prices too. ^
My experience with them (at least in the UK) was that they go around the car with you and note any bodywork defects on a sheet of paper there and then. You are of course welcome to point things out!
Generally, though, there are relatively few places/situations where you really need a rental car. 90% of the time I use a combination of public transport and taxis...No speeding/parking worries, no getting lost, no trying to figure the local driving customs out.