@daylightco 

 I use google play book on my phone, you can load your own pdf and epub in it. I find the ebook tablet like kindle overprice for what you can do with it 

 Kobo. It's cheap, works, lasts and accepts epubs without DRM. 

 I concur.  I love my kobo.  Works perfectly and I can back it up to my computer.

Also, #fuckamazon 

 I would recommend Kobo 

 For mobile? Which OS? or a desktop OS? 

 I think for epaper hardware 

 I still use an old kindle 3G with Keyboard. I think it mostly depends on the sources of ebooks you use? 

 Amazon Kindle