We were using a 'car share' program for the last couple of years, we decided to get a car instead and ditch the program.

My biggest problem was that the cars always had 1/4 of a tank of gas, so I was always filling the tank and using 30 minutes to find a station and fill the tank. Whenever I needed a car I needed to plan ahead significantly. Also, there is a stop loss incentive, so you get stressed about having to add extra hours to the car. We found if we are using the car more than 2 times a month its better to own a car.

Also, I hate the concept of calling it 'sharing' there is no sharing here, its a short term rental, all-be-it more convenient than traditional rentals.