Robin,
All you personal details, Name, address, email address, credit card and bank details are held by PayPal ONLINE.
When you pay by paypal all your name and address details etc (Not CC details) are sent to the vendor. (So no different to filling in a online form. (The vendor has to destroy the CC details once the transaction is complete, unless you give permission otherwise , I don't think it has to destroy your PayPal account details) The vendor may or may not keep your address details.
I don't think Paypal security check any transactions, so every payment request goes through, I know the CC companies do as they do look at patterns etc (and put suspect transactions on hold). Also with CC's you will often have to ender a password when the order is being processsed (Verified by Visa etc)
If your Paypal account get hacked, your accounts will be emptied … and you have to prove that it is not you …. (Not a easy task) If you loose you card, most card companies will refund you.
So in my view Credit/Debit Card is more secure.
Now the main issue — If you have a problem … try getting a refund from PayPal … The CC company (or Bank) are usually not interested as they are dealing with (in effect) another bank.
I have had the situation where paying for something with Paypal which was then refunded as the supplier could not supply … The refund payment was rejected by paypal … no reasons given … in the end the supplier had to send me a cheque … Paypal were just not interested, they had got their fee…. (Which they did not refund to the supplier)
Don;t get me wrong …. I still use Paypal as it is quick and easy … but I am quite happy in paying online with my Credit/Debit Card … after all the likes of Amazon don't accept Paypal.
Dave