E-ink is excellent for daylight use. I still have some issue with diffuse overhead lighting (e.g., fluorescent lighting). Detail is high, battery usage is generally low. Frontlight gives excellent indoor / dark ambient legibility.

The way I describe it: persistence is free, pixels are cheap, paints are slow, colour is (mostly) nonexistent. I find the interface far less distracting than emissive displays.

My own leaning is toward the dumbest phone I can find (though an e-ink display would be excellent), an e-book tablet, and a good laptop. Tablets are excellent for reading in ways that neither a smaller phone nor landscape laptop are.