I have now switched to it as my primary workhorse machine. The 2013 Mac Pro with upgraded 3.3 GHz 8 core is for sale, along with the NEC PA322W 4K display and one OWC Thunderbay 4 (5TB drives optional).
I use or will soon use all these forms of storage for home and on the road in my Mercedes Sprinter photography adventure van.
I use the NEC PA302W as my primary display for its wide gamut and many other excellent features. The iMac 5K is a viewing display not well suited for evaluating images for detail or color (can’t even control the brightness properly, for starters, plus pixel density).