Well, here's a small 'topical' topic...
I've just had to remove the ID from NUMS after I discovered the batch I had were VERY poor quality.
My usual supplier was out of stock, so I took a plunge and dealt with another wholesaler—who were DEARER per-deck—and they even delivered quicker.
However, upon inspection (yes—unlike most magic box-shifter, I actually CHECK the stuff I stock) I noticed the ID's didn't contain 'a routine'. On further inspection I noted the cards didn't actually 'work' mechanically as easily as my regular brand.
Ergo, they are off line, and on their way back for a refund.
However, my regular brand are on the way back into stock—badged up and including the routine by Daryl (yeah, THE Daryl uses ID's too

).
Over my short time in the 'retail' side of magic, I've noticed the quality of magic accessories is divided by a HUGE gap... ranging from the horrible to the exquisite.
I feel honour bound to supply the best quality at the best price, and I'm sure that's the reason you see some dealers selling items far cheaper than others—because there IS a diversity out there.
My mother in law (bless her) has a fantastic phrase which actually makes a lot of sense, which I'll share with you as an end-note:
Buy cheap, buy twice.