(reposted as my account since i accidentally was AC)
The scariest taxi ride I ever had was in the Seattle area, heading back to the Airport after the C++ conference. The taxicab was a Prius which was broken and dirty inside - you could see the airbag. The car's signal lights did not work. The driver was weaving in and out of traffic and just about killed a couple on a motorbike, causing a big road rage incident. The taxi driver was angry that we didn't tip him. If we had tipped him a normal amount, then the total cost of the trip would have been the same as the Uber ride that we took from the Airport to the same hotel.
As a consumer I want the choice to choose a safe, reliable, and trustable source. For me that is Uber.