I have been using PCS for the last few years and there are pros and cons.
The good: Their prices are great. An oil change is $15 and an oil change w/ tire rotation is $20. I can't remember exactly how much they charged for my brakes, but it was a great deal. Also, I once had to bring in my car because it fell of the jack when I was changing a flat and the heat shield bent in and was scraping the rotor and they bent it back for free.
They are also right next to the Triskett Rapid Station, so you can drop off your car and hop on the train and then pick up your car after work.
The bad: I have never had any major problems with them, but I am starting to suspect that their service is going downhill. For example, I brought in my wife's car for an oil change/tire rotation last a couple of months ago and we later discovered that they never did the rotation (she had a slow leak in her front passenger tire and after the rotation the same tire was in the same spot).
There used to always be a bald guy w/ piercings and tattoos that seemed to be in charge and their decline in service may have to do with the fact that I never see him there anymore.