Yeah its all great for the seller within the US. However for those that live outside the US and buy the system isn't as great. Ebay tacks on their "fees" to cover this service plus charges you the maximum amount of import duties every time since they forward that money off to whatever the importing country is.
When I buy something from ebay (when a seller is willing to ship to Canada) and it comes via the mail I get charged import duties maybe 50% of the time. Just depends on the Canadian Customs official reviewing my package to charge duty or just send it on its way.
However if it comes UPS you get charged the full duty amount PLUS Ups's ridiculous brokerage charges. I've paid more in brokerage than the part I bought in the first place. UPS is terrible in Canada.
Ebay brought this in to open up more people outside the US to be able to bid therefore driving the bids up (good for the seller) and make more money for ebay. Everybody within the US wins. Outside the US, depends how badly you needed that part