It depends on the country you live in. The fees are usually different for different regions. They also change frequently. I did a calculation a while ago for Germany and figured that any transaction below 100 USD is cheaper via PayPal, anything above is cheaper via Payoneer. But I cannot even say if that still holds true because since then I have received several emails regarding change of policy, likely including fees as well.
Unfortunately they are not super transparent either e.g. the fees are partly hidden in lower currency exchange rates than average and they are not listed anywhere, so it is not too easy to compare allover.
I mostly use Payoneer though because I feel they are more customer friendly, the transactions are faster and I have heard multiple times of PayPal withholding money for no reason.
Just seen your question even though it's a year old, but this answer may be useful.
If you're outside the US, PayPal will probably hit you with high currency conversion fees, but how high it is depends on the country you're in. When I was based in Thailand, PayPal were charging around 5-7% to transfer into my local bank account. PayPal sets its own currency conversion fees.
Payoneer has a flat % for currency conversion. I think it's 2% (can't quite remember, but you can check on Payoneer's website). And they base their currency rate on the real currency exchange rate.
So, Payoneer for non-US residents.
Hi - I'm from the UK too, and have just opened a Payoneer account thinking that the fees will be less than PayPal. What's your experience on PayPal v Payoneer re: fees and service for UK instructors? Thanks.