Barry, unless you feel that positive feedback for the buyer is contingent on likewise positive feedback for you, why not post it upon the timely and satisfactory receipt of payment? Of course, I guess the question would be if the buyer never received the article or was dissatisfied with it and posted unfavorable feedback for you - after you've posted nice words for him (or her), what then?

So far, I've left feedback upon payment, and haven't had to deal with the dilema yet.

Dave