I had somebody pay me like this once, it took about 7 days, then paypal said the payment had failed. The whole time this was going on the buyer was chasing me to find out if I had posted it and threatened bad feedback as I had taken ages to post it.

This is only my experience, and my advice would be to beware and only post once the payment was clear.

I couldn't understand that if they had a paypal account and so did you why don't they just make a straight transfer of pay by credit card like most others???