The experience wasn't entirely bad; The waiting area was nice and well stocked, they did a recall repair while the car was in, and they patched a tire for me for free.
The rest was absolutely awful. Scheduling the appointment itself was unpleasant - when I first called to make a reservation, I was told reservations weren't required. I called later just to make sure, and lo and behold, reservations were required. The personnel answering the phone were either unhelpful (gave inaccurate information) or rude. The Groupon was for an oil change, car wash, and inspection. You'd expect it to take what, 20 minutes for the oil change, 20 for the car wash, and 30 or so for the inspection? About an hour or so? Wrong. My wife was stuck there for THREE AND A HALF HOURS. It was obvious that full paying customers were put ahead on the priority list, with many, many customers checking in later and leaving sooner than us. My car's check engine light was on, and I was hoping they'd check it and let me know what the problem was- even Autozone does this for free. Nope. They noted that the light was cleared on the inspection form (was not cleared when I left with my car), and did not note what the problem was, or even the error code so that I could look it up on my own. A third of the Groupon (and a major reason I purchased it) was because a car wash was included. They did not wash my car. At all. Not the inside, not the outside, not the windows. It was every bit as dirty as when I turned it in.
If I hadn't been in a hurry to get to a dinner event that I had planned (remember, this took two and a half hours longer than I expected), I would have stayed and pointed out that they did not clean my car, didn't clear the check engine light, and didn't bother to let me know what the error code was. And to top off the whole experience, at every point during the absurdly long process they tried to upsell us, and convince us to have more services done.
Honestly, this is one of the worst experiences I've ever had with a business.