[Tarana]

I don't understand. If you want a unit for 'just reading' why do you NEED customization? Any Eink reader is your best choice for comfort in reading and battery life. The only difference between most of the readers is how they allow you to shelve your books. Maybe you need to be more specific about the type of customization you think you need.

I personally am getting out of the habit of carrying a large library. I just have about a dozen books plus all the books of a series. Everything else is stored in Calibre. Sony had the BEST shelving system, followed by the Kindle. It's not that I don't like Nook's shelving system, but it doesn't take it off the main listing, so you don't know for sure if everything is shelved or not (lots of people have 300 books on their readers, so it's important to know that).

edited to add: The non-lighted eink readers are more battery efficient than the lighted ones. They also weigh less. If you have generally good lighting where you read, I wouldn't bother with the lighted one.