Ebay Blues

Disturbing experience on ebay. I've been carefully cultivating my ebay rep, paying instantly on auctions I've won and packaging & mailing stuff I've sold like a true professional. Excellent 100% positive feedback. Recently I bought some software on ebay at a great "buy it now" price, listed as "New full retail version in box" with a picture of just what I needed (software purchase necessitated due to computer crash & reinstallation of XP...it was a nightmare but that's a whole other story.) Anyway, Hooray! I found what I needed on ebay, as usual. But the software the seller sent was SIMILAR to what was listed, not THE SAME AS what was listed. After some glitches I got the thing to work so no harm no foul. BUT in good conscience I felt like I could not leave positive feedback for the seller, nor could I leave NO feedback because some other unsuspecting buyer might have the same experience I did. So I left neutral feedback, no shouting, just the facts ma'am. And the seller in response gave me negative feedback, shouting about what a terrible customer I am!! This when I paid the buy it now price & got something other than what was listed!! It's so annoying. Now I'm at 96% instead of 100%...but there's nothing I can do about it (apparently.) So I'm venting here. Now I have to go sell and/or buy a bunch of stuff to get my rating back up. So if any ebayers are reading this, what do you do if you get a bad deal from a seller? Do you just swallow it & not leave any feedback so they won't destroy your reputation, or do you always leave feedback & be honest about it???