I like to go where ever, when ever, so I always get a car in Mexico. In PV / NV the roads are very easy to use. I like Bucerias, Punta Mita, Salulita , San Pancho and Guyubitos to the north and even though I have driven quite a ways south there hasn't been enough to hold my interest for return trips.
Going to the different stores for groceries is interesting. I doubt that I would go to so many places, including the Walmarts and the likes, without a car.
PV,NV,Cabo, Loreto, Cancun and Mazatlan were explored thoroughly because we had a car. The car trip from PV to Mazatlan was very scenic. The car trip from Loreto to Cabo was very scenic. The trips to La Paz and all ver the Baja were fun. My point is I couldn't have seen so many places without a car.
I like the Amex car protection but also purchase trip insurance that includes medical coverages and other benefits.
No car is allowed on the road in Mexico without liability insurance. If your in a rental car it will have 3rd party liability insurance as the law requires this. Avis and now many other car rental agencies include this minimum 3rd party liability insurance in their rate. Alamo does charge for the 3rd party liability but does have nicer cars similar to Avis. The Avis / Alamo rates are very close because of the required 3rd party liability insurance from Alamo.
If you rent a car from an outside unofficial website like expedia, rci, orbitz and the like you many be required to purchase the entire insurance package. It seems better to rent from the official rental car site and look at the terms and conditions. Print these off and take them with you as the rental car agency may try to force you to purchase insurance. With the printed off terms and conditions they will maybe try to scare you into purchasing insurance, but for me anyway, they just follow the deal I made online through their website without any problem.
Look the car over and take pictures. I take pictures and a short video because its so easy to do so with my phone. Two years ago Hertz said I damaged a wheel. I showed them the picture of the wheel when I rented the car and it was already damaged. They actually thanked me and apologized.
Most importantly, do not drive impaired. Just like in the USA, if your caught driving drunk you may end up in jail. The difference being that in Mexico you might get away with it if you give a donation wrapped in paper and no one was hurt and nothing was damaged. Never hand a cop an open bribe. They do not like this. It needs to be concealed. It is very rare that a person is pulled over in Mexico for nothing.
Bill