I currently paddle an EZ and I'm moving on because it is so uncomfortable. That might have something to do with how tall I am, but newer boats fit me better. I may keep it for teaching people in, but as was said above, I wouldn't buy a boat for that purpose.
Keep in mind that boats sell for different prices in different places. If you are in an area with lower demand, use that as leverage for whatever boat you are buying, and make the seller worry he won't sell it to someone at a high price, so he might as well bring the price down.