Best Goodwill I visited in Charlotte area and let me explain why...
The Matthews Goodwill is in a relatively prosperous part of town (near Providence and McKee Rds) and then donations they receive outmatch what you find at other thrift stores. It's not uncommon to find gently-used men's Gap, Banana Republic, and Brooks Brothers shirts and pants. While other thrift shops have "vintage"-looking clothes (I'm using vintage euphemistically here), this Goodwill has clothes that pass for brand new.
Also, the book selection is quite amazing. They sell hardbacks for $1.40 and paperbacks for .99! I've found some pristine books that may have been read once. Even if the store is out the way for you, you'll save major $$$ by purchasing your books here rather than at Borders, B&N, or other new book retailers.
The service is typically amiss for Goodwill-the cashiers are indifferent if not downright unprofessional. The furniture is overpriced, so don't waste your time looking for a steal here. Otherwise, this Goodwill is A-OK with me.