I've always had very good experiences w/Ebay/PayPal from the buyer's side. The seller's side is much worse, regardless of your feedback rating.
Unfortunately, PayPal gives the seller 90 days to respond to the incident and they are extremely slow at processing claims. You may be without your money for 3-6 months.
Here is probably the best link you will ever run across. It will speed up your claim 10 fold. Just don't be a prick on the phone and they won't ignore you.
302 Phone Numbers to Reach a Human at PayPal.
http://consumerist.com/consumer/leaks/302-phone-numbers-to-reach-a-human-at-paypal-307621.php