Earlier quoted context omitted.
I never had one, but doing some quick googling, it looks like at least some models had an e-ink display. Certainly several commenters seemed to think it did.
It was a transflective memory LCD, which Pebble marketed as "E-Paper" (not the same as E-Ink)
I've got a Bangle.js 2 at the moment and while I mostly like it, the screen is nowhere near as nice. Transflective is still very obviously what I want in a watch though, even the best oleds don't even come close in visibility.