WU is fairly straight forward and a lot easier than paypal, security wise. I've never been scammed through WU though I suppose it's possible.
WU payments you pickup at an agent and they hand you cash for it (I've had some, in grocery stores offer to give the money as a money order so you're not walking around with all he cash). So the chances of a fraudulent charge through WU are just about zero, but I wouldn't say impossible.
In the case of WU, I allow them to have the login/pws and nothing else (now, if they're also repped, I'll even agree to an email change at this time). I inform them that once I have the money in my hand, I'll hand over the last name, sq/sa, and email change (if I hadn't already done the latter).
Anyway, I'm getting off topic --- WU is a very secure way to do the transaction. Much more so than paypal.