I personally would not use a site that was posted by a brand new user like this.
I would personally suggest using purse.io, you can get a pretty decent discount.
Just wrote a quick review comparing these two services:
http://tabletsandtech.com/206/making-online-purchases-with-bitcoin/I would actually have a higher trust in all4btc since purse.io has no way to find out if the provider on the other end of the transaction is using illegally obtained Amazon gift codes. The best option from my perspective is to use all4btc with a merchant who has a generous affiliate program to order through (which unfortunately isn't amazon).