Quality is hard to find, but you can definitely find it at Mack's. The store carries both new and used books and allows you to look as long as you like. Mack's also has a fine magazine counter where you can find magazines and journals that aren't available at your local counters in chain stores. Some of the journals are available as used copies. It's great when you need a copy of a journal for a paper and the college library has misplaced that one or it isn't available on line.
The best part of Mack's is the service. If you are looking for a good read, ask the person at the counter. They actually READ! which is a rare case today in the big box and chain book stores.
Parking can be a problem, but there are usually parking spaces in the lot across the street and to the rear of the shops on the opposite side of the street. The lot is city owned and you will need change for the meters. Enforcement is tough, so watch yourself. You can feed the meter without getting a ticket. There are spots on the street, and directly in front of Mack's, if you get there near opening time.
Give yourself lots of time to browse because Mack's has some good reads!