Opinions are like assholes, ( everyone has 1),so here is mine. DON'T RENT FROM ANYONE!!! If you really need a car on and off during your stay here take a car with a driver form the taxi company at the airport. They have toyota sedans with drivers by the day. Like Dennis and Dustin say there are no gentleman's agreements here and insurance is a joke. Let it be their car and their driver, keeps you from being held hostage if there is a fender bender sir.

You can rent a trike by the day for a few hundred peso's from someone in your neighborhood and roam all over the city and then plan your time with a car carefully and pay the guys at the airport. Much less stressful and zero chance of you being responsible for rebuilding someone's piece of crap car and/or paying outrageous medical bills for whomever might get involved in even the most minor of accidents....