I used the Yellow Cab Company three times while in Steel Town. Twice from my hotel to meetings - and once back to my hotel.
The first time from the hotel - it took about 15 minutes for a cab to arrive. The Bellman at the Pittsburgh Renaissance warned me that it might take a few minutes and that I should give them a bit of a forewarning next time - as there are not a lot of cabs just around - unlike some other cities.
The second day from the hotel - there was actually a cab already at curb side - so I did not have to wait.
On the way back to the hotel - I called the cab company directly - it took about 25 minutes before the cab arrived. Luckily I was not in a hurry at this point!
Overall the three cabbies I had were friendly and efficient. Although this one cabby was eating a bag of some sort of snack while he was driving - and was loudly and obnoxiously licking his fingers after each reach into the bag.