The beauty is that you don't really have to trust PayPal. I usually transfer money out of my PayPal account within minutes of it arriving there, and I have made sure never to authorize PayPal to withdraw from any bank account I have.
Just make sure you have a backup plan so that if / when PayPal suspends your account for some stupid reason you have somewhere else for customers to go.
My sister sold some concert tickets on ebay paid for in full on PayPal. The guy came to her house & picked up the tickets and my sister withdrew the much needed money from PayPal.
About 4 weeks later my sister started receiving many e-mails from PayPal which, as she had no further business with PayPal, she assumed was spam and just ignored them. About 2 weeks ago she received a letter informing her PayPal has listed her with a credit reporting agency (yes, that means no credit cards, phone plans, mortgages for 5+ years) because she failed to pay them back $500 --- the guy had collected the tickets from my sister and saw the concert but then the bastard called PayPal to say he never received the tickets! PayPal simply put my sisters account into negative and started collections proceedings. When my sister finally figured out what had happened she explained the situation to PayPal & they just said too bad she didn't have proof that she gave him the tickets.
So yes, if you withdraw your money it makes it harder for PayPal to take it away from you, but that doesn't mean they can't screw you financially just for using their services