Great place if you just want an oil or transmission flush, but for major repairs look elsewhere. I had them take a look at my car, and they recommended that I replace my front lower ball joints and fully replace the rear brakes (drums, shoes, cylinders).
After buying the parts and taking it to a more trustworthy mechanic (brother-in-law), we quickly realize that their assessment was bogus. Moral of the story is always get a second opinion, especially for this place! I saved myself a repair that would ahve been over $500.
I have used Precision tune mostly for oil changes. Although you can (and sometimes should) make an appointment, on their slower days they will put out a sign for discounted oil changes (around 12-13.00). This can be a great deal for an oil change if they are running the special. Otherwise they usually have coupons in the mail, circulars or the paper. They will tell you if there is a wait, and if there isn't it can usually be done in 30 minutes or less. I would recommend calling ahead, but if you see the sign out, I would definitely stop in if you need an oil change.