I agree about deluxe and other sets.
But. If you have a look at stamps you'll see they have a... surprise! kinda a special labeling: for instance beveler B701 marked as "Z-B701" etc. All these have "Z" prefix and they sucks.
If you going to buy b701 from tandy (not as part of the kit), you'll see no such "Z" on the handle and ... it will be a bit different tool. Not a Barry King, but a bit better than from the kit.
So there are my 2 cents.
PS I believe "Z" means something like "Zero quality" or might be "sukZ"