It does not appear to be e-ink, and they do not claim to be e-ink... The kickstarter mentions a backlight, which makes me think it is not e-ink.

I can't say for sure, but the display appears to be this one: http://www.sharpmemorylcd.com/1-26-inch-memory-lcd.html or something like it.

It's an always on display with ultra low power consumption for static displays, so I think that is what they basis of the e-paper name. Seems a little dubious to me, but the watch still is very neat.