A rental car is by far my favourite way to discover Cuba. It's so simple to get off the beaten path and into cool places that rarely (or never) see tourists. IT'S NOT FOR EVERYONE THOUGH!!! Here's a few thoughts...
VERY IMPORTANT: You should be a very experienced, competent driver who can handle a manual transmission and know how to change a tire before considering driving in Cuba. Most rental agencies have a minimum age of 21 years for drivers, for some expensive rentals the minimum age can be 25 or even higher - in any case no one who is light on experience should be getting behind the wheel.
MOST IMPORTANTLY, do your due diligence with proper research so you make an informed decision whether a rental car makes sense for your style of travel! BE AWARE THAT UNDER CERTAIN CIRCUMSTANCES A CAR ACCIDENT CAN RESULT IN HUGE HASSLES!!!
1.) Click here, http://travel.gc.ca/destinations/cuba then go to "Laws & Culture" and read the reminder under "Vehicle Rental" that you are totally responsible for your rental car - even if you're not driving - and if anything happens you may not be allowed to leave Cuba until all bills are paid.
2.) Google, "Cody LeCompte" and "Damian Buksa" as examples of tourists making REALLY bad decisions that resulted in lengthy detentions in Cuba.
Bottom line: Cuba is a developing country with a road system and traffic laws much different that what you're likely used to at home so proper research is important, especially for a first time visitor. Don't be a dummy, travel smart!
Other Transport Options: If a rental car isn't for you there are other options like the Viazul Bus which is one of the few things in Cuba that works (mostly) as advertised and it services all the major centres that any tourist would wish to see on their first visit. Have a look here for some of the many other alternatives to travel around Cuba:
That said, here's why I love a rental car...
1.) Picking up hitch-hikers is a gas. I've gone to family reunions, retirement parties, weddings, funerals and every other situation that you can possibly imagine thanks to hitch-hikers. One time I took a lady 450 km to visit her sister who she hadn't seen in years. On their property they had a cave where we drank cold beer and fed the bats food on little pointed sticks. Another time a lady just kept driving and driving and driving with me, saying "not too much further" about a hundred times. As it turned out she didn't want to get out of the car because she had never felt air conditioning before. She also drank like a fish, finishing off a cooler full of beer then peeing back into the cans before throwing them outside without me knowing, but that's another story.
2.) Lock all your stuff in the trunk for security, but also so there's more room for people inside. I have a collapsible cooler with ice and cold drinks. A bottle of water is a luxury for someone who has been baking in the sun on the side of the road for hours with small children. Having a few snacks for the kids is nice too.
3.) Getting lost is fun. If I'm not on a schedule I navigate more by compass than by road map. Who cares where you end up?
Other Important Stuff:
1.) As soon as you land at the airport buy a road map. The best is "Guia de Carreteras."
2.) When you pick up your car be sure that every scratch and nick is confirmed on the contract. Take photos from all sides. Snag a couple of shots with the rental guy in the photo. Check the spare tire and confirm the tools are there to change it. Check the air conditioning, the radio and that all the locks work. Is the antenna in place? Do the headlights and turn signals work? Don't be afraid to be really picky. If something doesn't work or is missing either replace it, get them to fix it, or have it recorded on the Rental Contract so you're not hit with the bill later.
3.) Be sure all legal drivers are listed on the Rental Contract. Don't allow anyone to drive who isn't confirmed on the contract.
4.) Do NOT lose the Rental Contract. Keep it just as safe as your Passport. Losing it means lots of hassle and a fine when you return the car.
5.) Always park in a designated area where there's security. It's cheap and good insurance. If anything happens it makes the police report very straightforward.
6.) Driving at night is dangerous and should be avoided unless it's an emergency. Potholes that can break an axle, other vehicles with no lights, animals and everything else on the road.... it's doable, but drive slowly and cautiously.
7.) A two lane paved road in the middle of the country can simply end with no warning. Potholes can be gigantic - you don't want to blow a tire.
8.) With poor to non-existent signage passable Spanish is a definite advantage when asking directions, etc. but if you're adventurous you can get by with a dictionary or phrase book. (This is when hitch-hikers can be really helpful.)
9.) Use the same common sense when picking up hitch-hikers that you would anywhere. I usually only give rides to the elderly, Moms with kids or some poor soul stuck on their own out in the middle of nowhere.
Use common sense, do your research, MAKE AN INFORMED DECISION WHETHER A RENTAL CAR MAKES SENSE FOR YOUR PARTICULAR STYLE OF TRAVEL and have fun!