I leave feedback when I ship the item and I imagine I get around 50% or less. But I don't care too much. The more feedback, the higher the odds of someone not liking something or something random happening, and therefore the higher the odds of a negative. I am a top-rated seller already, so that may have something to do with my blase' attitude, but it may also be due to the fact that ebay basically is always looking for some way to screw sellers and I have been screwed by feedback before.
And now starting in August I am getting ready to be screwed if someone opens a case because the PO lost their item and I refunded their money.