After trying a handful of quick-change garages in the Charlotte area, I think I have found the spot to go to from here forward. From the guy who came out to my car before I'd even pulled in completely, to the technician that had me go with him for the drive to road test the tire balance and rotation, I think these folks do a really solid job. No more steering wheel vibration!
Waiting in the customer waiting room (there's a TV and free wi-fi), another customer had some major stuff going on with her car. They did what they could to prioritize the work so that the important stuff she could afford got done. She seemed pleased as well.
$59 for a full oil change with balancing and rotating the tires seems pretty reasonable to me. I'll be back.
If you are having more serious work done that requires a wait, there is a Dunkin Donuts and a Taco Bell within a stone's throw. Other restaurants nearby too.