"<a href=""http://comma.ai/"">Comma.ai</a> is pretty sweet.  I came really close to buying one (+ a new Toyota Corolla) this past spring.  Was on the fence between that and a new Tesla"," leaning toward <a href=""http://comma.ai/"">Comma.ai</a> because of the difference in price.  The deciding factor came when the dealership told me it'd void the warranty", so I'd be on my own if the vehicle had any [completely unrelated] problems - that, and I had some uncertainty about whether an aftermarket self-driving device could lead to additional liability in case of an accident.  I wound up buying the Tesla instead, and I love it, but if the warranty/liability issues hadn't been there, I'd have gone with the Comma'd Toyota just to save some cash.  If Comma addresses those warranty/liability concerns, it will be an easy purchase for mainstream audiences.