Quality and customer service. In my old shop, ALL of my employees were quilters and were able to help my customers with questions, etc. Wash a 4" square of JoAnn's/Wal-Mart fabric and one from a quilt shop. Measure them when you take them out of the dryer. Also, the JoAnn's/Wal-Mart is more apt to bleed and fade on you. If I am making a quilt for a family member or myself....it is always LQS quality fabric. If I am just crafting, I can justify the other fabrics.