I have been using PayPal for some 10 years now.
Do I trust them........most definitely and why......because I do not have to keep giving out my personal info to sell and buy off different sites.
PayPal also makes it very easy to do business with clients in Canada, the U.K. or even Czech Republic. All I have to do is send an invoice by email and the client pays in his currency or US Dollars, which ever is prefered.
PayPal has it now so you do not have to have a PayPal Account to be able to purchase using PayPal.
This really simplifies selling to foreign clients.
I do have to send a 2nd invoice for shipping and packaging but that is a minor inconvenience to be able to have clients all around the world.
