I'm not a Pittsburgh native. Yellow Cab was the only taxi company I recognized so they were my first call. I called for a cab at 4:30AM (!!) and had someone at my front door in less than half an hour. Very impressive. Cab driver was great. We talked for a little bit before I nodded off for a nap.
Given how far he had to drive, the fare to the airport was reasonable, the car was clean, and the driver was professional. Can't ask for anything else in a cab driver.
I will use Yellow Cab again when I'm next in Pittsburgh.