For the seller bank transfer is much safer. It usually takes 3-4 days and once the money is in your bank that's it, the buyer can't get it back. It's as good as being sent cash.
Paypal is really good for a buyer but a pain in the butt for a seller if you sell on ebay - the seller can say the goods haven't arrived and paypal will take the money back and it's up to you to try and persuade paypal that they have been delivered
If you comply with paypals seller protection rules (you must send the goods so they are trackable online and to a confirmed address) then paypal will give you the money back once you've sent them all the proof they need.
Outside of ebay the rules are more vague as the chargebacks are part of ebays policy to make it safer for ebay buyers so paypal won't just give in to the buyer. If they then try to get their credit card company to take the money back from paypal it's not that simple as the deal of transferring money to paypal worked fine and what happens to that money afterwards is nothing to do with them. If they do get a chargeback through their credit card company then paypal will take the money it has lost back out of your account, but the buyer usually then finds their paypal account is frozen so they have really got to take the risk of not having a paypal account.
If he sends UPS to collect it once it has been collected any problems are between the buyer and UPS, not you, as you will be given proof that they collected it.
For a seller this has to be the safest deal there is, a secure way of payment and no problems dealing with goods lost in the post - perfect!
