I've had similar experiences. In most cases I reach an amicable agreement with the person filing the dispute. But when it is contested further, Paypal sides with me (the seller) well over half the time.paypal ALWAYS sides with the seller on the sale of digital goods (because intangible items are not covered for protection)
Problem with paypal (I don't know if they still do this...) Is sometimes when someone opens a dispute they will take out the funds from your account immediately and put it on hold. They use to send that money back to the buyers account and what would end up happening is the buyer would withdraw the money to his bank account and even if I won the dispute, they couldn't get the money back and they would tell me... "Sorry we can't do nothing he doesn't have any money in his account.." I hated that shit... I think they may have changed this process to give sellers a little more protection although I'm not sure.
I recently got this email from Paypal:
Thanks for the information you provided on this chargeback. As always,
PayPal will help you dispute unwarranted chargebacks, so we've contacted
the buyer's card issuer and opened a dispute on your behalf.
Usually, when a buyer files a chargeback and the card issuer reverses the
charge, we temporarily hold the funds until the issue is resolved. However,
because of your low dispute rate and consistent sales volume, we're
allowing you access to the funds while we investigate the chargeback. We
want to extend this courtesy to our valued customers, because we know how
inconvenient it can be to have your funds held.