I have used this Greulich's location because it is close to where I work. They provide complimentary transportation to and from your place of business within a reasonable distance (I work about 2 miles away - I don't know how far they are willing to go). Their web site always lists a coupon for an oil change for $15.88.
I had them work on my Mazda 3 on 12/27/2011. I brought it in for an oil change and asked them to change the cabin air filter and the engine air filter. They claimed that my vehicle does not have a cabin air filter. I found out otherwise on the internet when I came home. This caused me to question the other work they performed. The oil was indeed changed. The engine air filter was not. It was filthy!
I called the next morning to advise the store manager. He agreed to refund the price of the air filter. I did get what I wanted (I.e., the refund). Did I get an apology? No. Was the manager at all embarrassed by the mishap? No. Did I get an offer for a free oil change the next time? No. Given the viral nature of social media and the choices we all have, I would have expected the manager to have made every effort to keep me as a customer to prevent me from doing what I'm doing now - letting the world know about my less than acceptable experience.
If you are going to use them, i would only use them for oil changes, tire rotations, etc. I would recommend that you check the work, ask to see the old parts, etc. if you are going to use them.