Calling a cab in San Francisco is a miserable experience, especially if you're calling from an area that attracts fewer rides. If you can get ahold of a dispatcher, there's no guarantee a cab will even show up. And after making the call, you have no way to assess how long a taxi may take to arrive. With Uber and Lyft, these are not problems.

I've never ordered a taxi in a small town, so I can't comment on what that process is like.