eBay feedback - Sellers post first
This is a pet peeve of mine. I've been an eBay user for over a decade, more often a buyer than a seller, but I've sold quite a few things there. It frustrates me to no end when a seller withholds feedback until they receive it.
First, you are the seller. eBay puts you at a disadvantage in general. Everything is geared toward buyer satisfaction. Your provide the product. Your feedback is not as important and the buyer's satisfaction.
Second, the buyer has bought the item. Paid for it. They've done their part. That's what you're rating. So rate it. You are not rating how annoyed they get when you screw up the order, or how nice they are when you take two weeks to ship the item. Waiting until you've received your feedback is holding their feedback hostage until you get what you want.