I just got a DX7 in perfect condition. Not the "easily" programmable module, not the better Mk II with stereo and duo-timbre, not the 100 year edition with the colors, but the plain old Mk I. And I think it is the best version you can buy, for sentimental reasons. With a bit of reverb, the presets sound amazing, I downloaded a manual, let's see how far I get...