Being hit with a $150 service fee when a car I had thought I'd parked in the right place (and yes, the car let me end my trip), along with the ticket and towing fee (amounting in total to over $320), means that I'll try to avoid using this service in the future. Any money I'd saved by using Car2Go instead of cabs has been flushed down the toilet.
As others have said, it seems cheap, but they'll nickel and dime you all the way to considering buying your own car.