While the post is very good and helpful, I'd like to add that as someone who has been using Paypal for international transactions (of different currencies, that is), I've been paying quite a lot of service and exchange fees to Paypal, and it's not always worth it. Paypal have increased their international transaction fees to up to 10% (!) of the total amount paid, which is absolutely insane.
Therefore, I recently started using Stripe, which is basically a credit-card payment platform, if I understood correctly. Their fees are much lower and more competitive than those of Paypal.