I use a Hanlin V5. 
(Hanlin V5 is the Chinese name, but it is sold under many names,
such as Astak, BeBook,...)

It can read DJVU, PDF,... The 5"-screen is sometimes a bit too small for some of the texts, and the machine is sometimes a bit slow, but it works.
The storage is short, but it can be enlarged easily via the SD-card slot.