I just pre-ordered a Bigme 13-inch color e-ink monitor with a 30Hz refresh rate. At $499, it's much cheaper than the Dasung, though the quality and e-ink display algorithms might not be as good
I've been using a BOOX Tab Ultra C Pro (with the Kaleido 3 color e-ink) for a year. The colors are quite dim, to the point where I sometimes forget it's a color e-ink display. The Colorsoft display looks significantly better in comparison (even seems to have better contrast than ClearInk?), so I'm curious how it works.