The bottom line is each branch will vary on performance and rip off scale dependent on who is managing that particular branch. Some are on the take and will charge for sand in the trunk, scuffs on the rims, a Ltr of gas under the original reading etc etc, some more stand up managers will wave it off and understand the value of return customers.
You can't go with a company name unless you know the particular branch. All offer more or less the same, but like everything else, that means nothing if there is a corrupt mind at work.
Sometimes when my friends or family visit, they rent a car for next to nothing from a friend of mine who imports cars from the US to sell. They have independent insurance figured out, but they can go where ever they like, even Haiti and know they won't have any BS if anything happens. If you can insure yourself and have similar connections then this can save a fortune and a weight off your mind.