As a buyer I prefer PP because I can pay half asleep, and the worst that can ever happen is it will not go through.  If I mess up DD the money can end up in wrong account and to get it back is not easy.

As seller, I also prefer PP; it shows whether the buyer paid or not, even if they pay by echeque, I do know they did (waiting does not worry me).  But if buyer says that they paid into my account I have only their word for it and no way to know if it is true until the money appears in my account, which means I have to be logging into my bank account to check.

Not to mention that PP makes my accounting so much easier.