What about Neteller?
Neteller itself don't have chargeback possibility but it all depends on the payment method used to fund the account. If for example someone fund his account using a credit card and then send you funds, If he contact the credit card company claiming the payment was unauthorized, there is a possibility that the will chargeback it and you will get affected. So, while dealing with Neteller, always ask for proof on how the account was funded. (If bitcoin for example was used, no fear).
Absolutely right!
No matter that transfer service is non-reversible (like Neteller or OKPAY), there is a possibility that the client will get chargeback if it was a payment via plastic card.
So this is not the fault of Paypal and it would be fair to change the name of the topic =)