I've frequented this Car-X multiple times (I don't have the best luck with cars...) and I've always had a great experience. The employees seem to-the-point but very patient and helpful if something needs extra explaining. I've had routine oil changes done, but my car has also seemingly been brought back from the dead (with no after effects) due to the great work of the staff!
This Car-X seems standard, at least to others around the city as well as around Chicago. Make an appointment ahead of time, and be prepared to wait at least an hour for an oil change.