Fairly popular amongst people I've chatted with, but I have also heard many complaints about shipping errors and I am proof of this as well. Spent a lot of $$$ and was shipped the wrong knife that was even cheaper than what I had ordered. Although, it was worked out with A+ customer service.
I announced my mishap and I received feedback saying that this has happened to a handful of people, but ultimately they come through.
Edit: I apologize, I am speaking of KnifeArt, not KnifeCenter.
The only complaints I have heard from Knifecenter is that they often list things as "In Stock" when they are not, which has also happened to me.