Perfect example of regulations not keeping up with technology. If I request a "cab" via an iPhone app, I know exactly how far I'm going and how much its going to cost me before I even get in the cab.
But they create incentives for good behavior and give those that have the time to plan information with which to make their decisions.
And for me, it's not even worth that. I just want a taxi that's insured.
I'm not against rating systems on top of what we have now. If it's worth it for you to wait a minute for a better cab, more power to you. (Hell, I might want to take some time to find a nice car if I were on a date or something.) But please don't take away the easy, efficient system we have now in most cities.