It also costs more than an iPad and has terrible response times

Yep, pretty consistent for e-ink.

Still, I think it has the best value proposition for an e-ink tablet at the moment, but I'd love to be proven wrong.

Probably true - I’ll snatch it up the moment color e-ink is a thing, color is vital for most of the papers I work with and for books I prefer a smaller form factor so from my perspective it sits in kinda an odd part of the market.

Color e-ink is close, which is really impressive imo. I did not expect to see it for years.

Who knows how long it will take to get good enough yields for affordable consumer products.

https://www.eink.com/color-technology.html