Personally I much prefer e-ink when I read for more than 10 minutes or so. The LED light from my phone just makes my eyes tired, while e-ink + "backlight" (guess it's really "kind of from the front light" in reality) just feels like reading normal paper.

The font rendering in the official firmware isn't that great though, especially compared to even a old phone screen. I had much better text rendering with 3rd party firmware.