After reading few books on my phone and more than a few on stand-alone eBook reader with EInk screen I feel quite capable of judging which one is better. In short - mobile phone sucks.
My phone has 3.7" screen and this is just barely enough for normal reading. As soon as I have need for bigger font size (I like to read while walking), phone fails me misserably. Screen is just too small.
BeBook mini was on small side of e-book reader and while 5" may not seem much, I consider it quite a good balance between portability and readability.
Reading at daylight
Lot of my reading is in sunlight. Anything not eInk is just painful. Visibility under direct sun is zero and shade improves things only marginally. Fingerprints on my touch screen do not help much either. I keep finding myself cleaning damn thing every few minutes.
Reading at night
Here is where mobile phone shines. Backlight is just something that you don't get with eInk. Kindle application even allows adjustments of brightness level and paper color.
Anybody saying that LCD is perfectly suited for reading probably never tried eInk.
- Yes, eInk is expensive.
- Yes, eInk devices are only good for reading.
- Yes, eInk has no backlight.
With all that in mind I still prefer it. For pure reading pleasure eInk is way to go.