This is my take on feedback. I disagree with most, not all, of the posts in the thread.

(1) eBay never seems to have given guidelines/standards as to when and which feedback should be given. This is all I could find:

"What is feedback? Feedback is made up of comments and ratings left by other eBay members you've bought from and sold to. These comments and ratings are valuable indicators of your reputation as a buyer or seller on eBay. They are included, along with an overall feedback score, in your member profile."

EBay probably has a good reason for being so non-committal. They probably are so deliberately vague to avoid arguments with eBay buyers and sellers.

(2) I, now, always generally leave feedback:
¶ as a buyer, after I receive the goods (whether the seller left positive feedback or not).
¶ as a seller, after the buyer has left positive feedback.

(3) In the past I, as a seller, always used to leave positive feedback after receiving the payment. Nothing wrong with that. It has its own logic. Many posters on this thread do the same. They say:
¶ "I maintain and always have that when you the seller has received payment for the mdse. you are selling, the obligation of the buyer has been completed. Your feedback should be based on that person paying within a timely manner."
¶ "The seller should leave positive feedback when they have received good funds."
¶ "I post feedback when paid. The buyer completed his end of the bargin and It is also my way of telling them I received payment."
If somebody holds feedback as ransom from me to leave first I just don't.
¶ "My half of the deal is done, feedback earned. period. MY feedback should pertain to MY PART of the deal, not depend on what/if I post feedback as a buyer."

(4) Now, as a seller, I always leave positive feedback only after the buyer has left positive feedback. That policy has its own logic too, not all of it manipulative or sinister. Since eBay does not say when and why feedback should be given (not that I would care what eBay says), I assume that positive feedback is given when one is satisfied with the whole transaction. To me as a seller, the buyer's responsibility is not just to make a payment, but NOT TO BE A JERK. It is no trick to list something, and it is no trick to pay for something! The big thing is for the buyer to be satisfied! I wait till I know he is satisfied with the item, usually indicated by his leaving positive feedback. If something is wrong, let him point it out, and I'll correct it if he is reasonable, in my opinion. To restate it, I, as a seller, wait for the whole transaction to be completed. The most important responsibility of the buyer is not his payment, but his reaction to the item.

(5) Incidentally, eBay says that feedback can be left after 90 days.

Robert