If it's purely text, it's subjective and perhaps more people will prefer e-ink. I don't mind either myself.

If it's articles with diagrams and colors or magazine layouts, with gloss and shine, nothing beats iPhone 4(s) and iPad 3's retina display.

I often have problems with eye irritation/fatigue after a long day of work and thought an e-ink device would make night reading easier. Got a kindle touch, tried it for a week. It was worse, without a doubt. I tend to read in dim light (indirect lamp), and found that the kindle needed direct light for me to easily read without eyestrain. iPad with very low brightness, or even in reversed accessibility mode is nicer. For me, that is. And, any book or paper with code samples just doesn't work well on a small e-ink screen.

I've been relatively happy with the IPS panel in the iPad 1 not straining my eyes. My main gripe is that the brightness of the backlight doesn't go low enough -- in a dark room (i.e. in bed with no lights and someone else sleeping nearby), it would be nice to be able to use the iPad with very minimal backlight. E-Ink would require a book light (which is kind of lame). This seems to be one of the places where OLED would be superior.

It's frustrating that IPS LCD, OLED, and E-Ink all have such distinct advantages, so the idea of having a single device with the best screen in all contexts isn't really possible. I assume OLED will eventually be that.

How can quadruple the resolution not be better for reading text? People who have compare it to looking at glossy print.

How is "more beautiful" not better? Instapaper's also one of the main reasons I'm considering an upgrade.

There's nothing inherent in e-ink that makes it less stressful than a backlit display. Photons are photons, whether they are reflected from a light bulb or the sun to the book and then your eyes, or they are send from a led behind the screen to your eyes.

Some early e-ink manufactures used to claim that e-ink is better than backlit for the eyes, but they retracted those claims because there was no scientific evidence behind them.

You just need to set the brightness of the iPad appropriately, to match what the relative brightness of an e-ink reader would be. You can also adjust the colors, i.e have a sepia background etc.

Battery life and reading in the sun is indeed much better with e-ink devices, though.

I had a Fire and really didn't like it for reading -- it falls in the valley of uselessness between a Kindle (DX being my favorite) and the iPad. I don't find my iPad 1 particularly heavy -- the main drawback of the iPad vs. Kindles is lack of daylight readability, and to a lesser degree, potentially distracting apps (email, web).

The Fire seems like a great video watching device, but I don't do much of that (and when I do, it's on a projector with surround sound and other people)

For books and papers in non western alphabet languages, the ipad is a much much better reading experience IMO.

Don't forget battery life.