Probably an offtopic for your offtopic, but:

I use my phone to read e-books:

- AMOLED screen (black color doesn't emit light).

- low level of brightness (so I can read in the night without "losing" melatonin). Usually e-book reading app gives you this option.

- the PDF reading app must have reflowing of the text, so you can choose the size and font you like.

- no blue colors (ie yellow "face" with a black background). Not sure about its effect, but everywhere I read about blue filters. 8-)

Orgzly I use to capture ideas; and other tasks related with auto-organization (GTD). Of course, the .org files are sync with my computer.

For reading org-mode documents on mobile, I haven't found the perfect app.