I own a lot of luggage. I'm constantly trying to come up with the perfect bag for my carryon travels. I had one from Kmart that was the cheapest, lightest piece of luggage I've ever owned but it finally ripped and Kmart is gone.
I'm always looking for a 21x14x7.8 inch bag. It's hard to find a bag that is those actual dimensions. I own about 4 bags that are close but just blow it one one of the three measurements. Usually the bag is more like 9 inches deep and that causes potential problems for all sorts of airlines...Condor, Lufthansa etc.
So I just bought the Tourister bag at Costco today. It's spot on in every dimension. It's going to Greece with me next month!