I go to Chammies at least once a month for their "whole 9 yards" car wash. Overall, they do a fairly good job. Sometimes before I leave I have to point out that there are streaks on a (usually back) window, but they are always happy to make it right.
I have also recently gotten my oil changed there. No only are they super-speedy, but the service technician is friendly and helpful.
My only wish is that they would offer more than a "dust" or "wipe" of the dash. I wish there was an option on their price list to have the interior well-cleaned or really detailed. Also, if there was a Chammies closer to the west side of Asheville, I'd go there more often.
My suggestions - look over your vehicle before you leave. And always tip accordingly.