Always rent a car expecting an attempted to be ripped off.
Know their rules and be nice.
I've had surprisingly good experiences with a company with bad rep.
Once i rented a car for 3 weeks for 0.73cents a day in low season. A fiat panda in south west europe.
Im local there so it helped.
Always make a chitchat with the person in the counter, get their name and ask them how i can avoid any issues.
They are surprisingly nice and i can always name drop their name to the final inspector so they think i know them.
... Or just buy their insurance.