Alex (TandemNut) knows the product well, but FWIW, I wouldn't pay more than $1200 for it. Reason is, there isn't one component I wouldn't want to immediately upgrade, and soon after that probably the frame too. The frame design is really old, rear shock old, no rear disc or mount for it. So why start with this ECDM at all? Well, if the buyer has absolutely no inclination to start the upgrade cycle, and can source maintenance for the old existing parts, then maybe. At this point in time (2019) it would be akin to buying a PC from 2000/2001... current ECDM design plus each and every part are that much better now then they were back in the day.
Anyone considering or even just curious, should check out Alex's build packages on
https://mtbtandems.com/. Very very reasonable. You can of course buy just the frame and build up yourself.