Just as any service company that deals with mass amounts of payments paypal has a buyer protection program, similar to large credit card companies. Now be carefull this is for ebay only, and you must be buying tangible goods, ie hard goods.
The only thing that is not a plus about this service is that paypal allows you to add this to any purchase. For example, you can add it to the purchase of an ebook. However, if the ebook is never delivered, sorry. And that is what paypal will tell you as well.
So just as a reminder you may check out the item thoroughly prior to making your puchase using this service, expecially if it is a big ticket item.
Hope this helps somebody out there.