The "quality" that everyone is referring too isn't saying that the airsoft gear will fall apart in your first game (although some stuff is that poorly made and will let you down).
It usually shows up in more subtle ways. MOLLE loops stitched to close so you can't thread pouches into all the slots, upside down fixtures, missing or otherwise non-functional straps and hangers. Stuff you might not even notice when you're a noobie but later on when you try to used it you'll find you've been had.
Airsoft, where nothing is hurt but feelings.