I've looked up zwee and I have to say it is a scam. They get paid for people visiting there site and I heard if you order something they usually tell you that it is sold out and they refund your money.
I have used this company for probably the past 6 years, although not as much recently. You have to know what you are doing and understand the salvage market, but if you do then you can certainly make moneywith it. My speciality is tools ( not always great for eBay due to weight).