Jim, the RoninMX was a great multi-role gimbal setup, but has sadly become a fading cinema gimbal for the “hand held“ teams, but remains a great mount for the M600Pro Owners seeking to mount DSLR or other large cameras.
That equates to a deflated value with a smaller Buyer market. On eBay there is a wide span... many feeling it has more value than reality. I personally own 1, practically new and came in a Nanuk 940 travel case. I see similar offered on eBay between $450-1000... avg $600-900. The non-case in box are about the same, avg $400-650... all depends on how quickly they want to move it.
When you advertise it, show the M600Pro mount too... many Hand-Teams tossed that and it now has value for the M600Pro Buyers.