I took my car into this particular Grease Monkey location for a standard oil change. While I was there they showed me my air filter which I had changed ~6 months ago and tried to tell me it was dirty and I needed a new one. I said "no thanks" and figured that was the end of it. After pulling away, I checked my receipt and noticed I had been charged for a new air filter which they hadn't even replaced. I guess this could have been an honest mistake, if not for this...
After completing my oil change, they explained to me that I had a rip in my CV boot and "an ASE certified mechanic could repair this for only $200." Realizing the value of a 2nd opinion, I asked a mechanic friend of mine to take a look at it. By his reaction, I could tell he was blown away. Grease Monkey had actually smeared grease around the boot to make it look like it was leaking. He wiped it off with a paper towel and the boot was perfectly fine, just like the others. These guys are scandalous. I wouldn't trust them to open the hood. Consider yourself warned!
Pros: No line.
Cons: They will try to rip you off.