Paypal has one +, and thats you dont have to give your card number out every time you purchase. If you are a serial purchaser then I can understand the thought of balance between getting stiffed by paypal, or getting stiffed because you card details got skimmed.
But use paypal with open eyes, read the TOS carefully, and read some of the horror stories on sites like paypalsucks.com just so you are aware of what "can" happen. Paypal cannot protect you 100%, the TOS is designed to cover them so if you are defrauded by a seller, PP will not be out of pocket. That means if the seller takes your money, clears the account and clears any bank accounts that may be linked to his PP account you are sh
t outa luck getting money back through PP. You will have to use your card company to do it, they will take the money off PP, and likely PP will get rather upset, close your account and ban you.
Personally for my bus' I refuse to use online portals for CC processing, I pay for security certificates and encryption and when you use your card on my site the numbers are split into 3 encrypted lots and sent to me separately, I run them through a physical machine in the office, no details are kept online, all emails are deleted.