I base my opinion on many, many years of having used Paypal and ebay with accounts on 3 different continents and I have no worries at all using either but then I completely understand how both Paypal and ebay buyer and seller protection work so have had the very few problems I have encountered resolved in my favour.

And guess what? All with absolutely no legal training, just common sense and the ability, and inclination, to actually read all the policies, terms and conditions and any updates as they occur.