I haven't bought anything on Preloved although there were a couple of items I enquired about that were already sold as the seller on both occasions didn't remove the advert but I have actually sold a wheel clamp and a pair of matching camping/fishing chairs on Preloved after having no success on Ebay.
I may be wrong, but I get the impression that those that sell on Preloved are targeting a much more selective market and those that are looking on Preloved are after particular and specific items.
I think you are right Lobey, its a much smaller scale of operation but one big advantage to selling anything on Fleabay is that its free, no fees are paid by either party.