I've purchased tens of items under the GSP.  I've had items shipped to me from the US weighing in excess of 10kg for US$30 or so - a fraction of what it would cost me if the seller shipped via normal means.  My only complaints are that FedEx tends to hold onto parcels for a few days since PBI only pay for economy shipping.  Items take 2-3 weeks travel from the seller to the destination so the transit time is roughly equal to USPS Priority Mail from the US.  While direct shipping from the seller is cheaper for small items, you can bet your life that GSP is *MUCH* cheaper if / when you're buying larger items, or large quantities of an item.