It seems the C67ML is not a popular reader... and I don't want to crowd the forums too much and since I just have a little to say, I'm adding it to this thread. I bought the C67ML from
Banggood.com as a gift for a friend who was in need of just such a device for ESL reading (she wanted to read and check dictionaries while reading).
I upgraded the firmware using the lastest one from
onyx-international.com and struggled for days to root it... until I finally found
this Japanese page. I was familiar with rooting my phone with Odin and the instructions are idiot-proof (even after auto-translating).
I also managed to find a few dictionaries and threw them on an old Micro SD card... they wouldn't work when I put the dictionary files in internal memory.
Overall, I was impressed with the device, too. And my friend also loved the ability to read Buzzfeed and Cracked... but she found the way the organizer worked tough... with time, she might have installed another library organizer something from the Play store but alas... the klutz broke it after less than two weeks...
I do note that her only complaint was about the speed... but compared to my well-loved PRS-505, it's lightning quick. So that seems to imply the display was readable, the backlight was good, and the Wifi and battery life were acceptable. Not really sure, but as I said, just sharing... mostly because the Japanese site rooting procedure worked so easily.
I personally would love to have played with it more... but I won't be doing so unless I give up my trusty 505 or repair the display on the one she broke... We'll see.