Ok, I briefly read that website and feel I need to explain what happened to me.
I paid for something and wanted to pay with Bank Account #1 because I didn't want to overdraw Bank Account #2. So, I paid for the auction and everyone was happy. I checked my bank account #2 status the next day and what do I find: I'm overdrawn by an amount that could only have been caused by the auction payment. Well, there is a very good reason for this (I called paypal for this answer). Basically, to enable you to make a payment directly from your bank account, paypal puts a hold on the amount of funds needed from your primary credit card on file. Paying with your bank account is no faster than writing a check in reality. In the days that a check would need to clear, paypal puts a hold on that amount of money, ON YOUR CREDIT CARD. Well, my primary card is a Visa Check card, which directly debits from account #2. So, I was temporarily with a negative balance in account #2 because a hold was put on that amount, on my visa check card. To make this clear though, a hold on funds that gives you a negative account balance will NOT actually overdraw your account. Only if paypal makes a claim on that money, will you be overdrawn. After a couple days, the hold on my visa check card was taken off and the money was taken from the account I originally wanted to use. No harm, no foul.
I also read on that site, from the horror stories page, about a guy that tried to use his mom's credit card with his name on his paypal account and was complaining about how his bank account was drained. I have no sympathy for this guy, IT LOOKS LIKE FRAUD WHEN YOU USE A CREDIT CARD WITHOUT YOUR NAME ON IT! Come on, how stupid must this guy be?
Anyway, I know that my experiences don't explain everything that goes wrong with paypal, but I think it accounts for some of them.