Before renting a car in Cancun (or virtually anywhere in Mexico) you must realize everything is different in that country. I have some previous experience and the old VW Beetles do not surprise me - just as I learned to handle manual transmission. I recommend established companies, for the sake of safety. Although they also often don't have the selection of vehicles you might expect, their cars are at least not dangerous to drive. I got a good service at Alamo and have no reason not to hire there the next time as well. They also informed me not to pay the tickets to local police, even if they try to take my license. And guess what - I got pulled off and the policemen tried to convince me (I could almost use the word force me) into bribing them (wanted $50). This, I learned later, is a very common way of making some extra income in Mexico. Never give them a dime!