Take a look at this video about the PocketBook Era:
https://www.youtube.com/watch?v=ENsVKPuH3EY
I have not used that device but have used the Touch HD 3. It is the most configurable ereader I've ever used. The buttons can be reassigned and also have 3 options (click, double click and long press) which have many options. You can get rid of the adds on the home screen. You can rearrange the bottom icons on the home screen, remove them or assign different functions or apps. The Library is great and works like a phone with an accelerator (instead of just jumping from screen to screen) it scrolls continuously depending on how fast you flick it.
When transferring books from Calibre it creates series and collections (as genres) on the first transfer without having to reconnect like the Kobo.
When reading a book there are nine tap zones which can be reassigned to many options. You can define all four swipe gestures (up, down, right, left). Dragging your finger on the right and left edges of the display can preform various user defined options (lighting, both warm and brightness, font size etc.).
You can add fonts.