I've only been to my local Apple Store in SoHo, New York City, but I've been there many times and it's always a great experience. From what I've heard about other stores, I think it may be one of the best stores. Every employee is always friendly and knowledgeable, especially the Apple Specialists at the Genius Bar, who are usually more knowledgeable than the AppleCare tech support people on the phone. There are not many good Mac stores in NYC, so the Apple Store was a wonderful blessing when it opened. :)
The Apple Store: Bad Customer Service at Your Local Mall, Part II