I deal with paypal often and there are no hidden fees *unless* you receive money from someone with a credit card: you need a premium account to accept the credit card payments.
If you trully want to read about the bad aspects of paypal, go to
www.paypalsucks.com , yet as far as I can see, those people have too much time on their hands: Postal Money Orders cost 3.50 CND each and take one week to get to their destination.