Definitely lower cost per mile due to the fuel economy. Clearly they make a ton of sense for taxis. Do you have evidence for the higher reliability than pure ICE cars? I hadn't heard that, and it seems counter-intuitive to me. I certainly know anecdotally I've heard many claims of Prius hybrid batteries failing. (Which isn't necessarily a huge problem, but just saying it adds a point of failure without, as far as I can tell, removing any.)