Lack of quality control will be the end of this line, if it ever does happen. The designs are nice, and there is something for just about everyone. The price isn't horrible, but the inconsistent quality keeps people up in arms. Some sets seem to just be better than others when it comes to thickness/heaviness, and color saturation, and painting/glazing. When people get good pieces, they get excited and try to keep buying and adding to their collection, just to be disappointed later when other pieces are terrible.
I never worry too much about buying from Q, because they have such and easy return policy, and never charge for returning defective merchandise, so you are out nothing but time and frustration to give something a try.
The Temp-tations web site is a different story. They charge for returns, sometimes even when the product is inferior and not up to standards. They say they are shipping out replacement parts, but often they don't come, are out of stock and waiting forever for replacement. I think the TT web site is just more difficult to deal with, and I don't order from them as much because of it.