You know, I'm not sure if I just have bad luck or what but I've bought big electronics via eBay that were not working properly - including an Oberheim Xpander that needed a bunch of work after the seller stated it as "mint", and an Alesis Q2, Wedge, Quasimidi PolyMorph, and a Nord Modular - at the time I just lived with the damaged stuff because I was too busy in life to deal with a fight - plus I'm not sure if eBay/PP had any sort of buyer protection back then. Anyway, yeah, you have to watch out, but I think the situation is a lot worse these days if you're buying. A lot of people are out to sell old broken heavily-gigged smoke-smelling gear and sell it as "near-mint". I try to find a good deal, but the problem is the sellers that have good deals almost never disclose issues with items.
Oh, and here's a new sneaky tactic that's being used - sellers are using images of different versions of items in the photo. I see this all the time with CDs & records. Sellers will use images for deluxe versions of CDs/Records and then in small print in the listing say "the photo shown is not the deluxe version"... so you have to really work hard to ensure you're buying the right thing. It's pretty bad actually. I don't know why the seller can't use an actual photo or find a proper one off the internet or discogs.com, so one can only conclude the seller is trying to trick you.