Alamo is about the same as Avis and others but you need to think about what sort of driving you will be doing. If you are going to be doing any significant inter-city driving, then I recommend you look toward one of the companies that have more locations around the island and/or a roadside assistance service. That flat tire at an odd hour outside the city can put a real damper on your holiday - and believe me, flat tires are fairly common on these roads. Check the websites for location information.