I would agree with @NiLuJe that you have nothing to lose by trying KOReader or Plato. I've tried both and they wasn't my cup of tea as pretty much all my ebooks are in epub format and render well as epub or kepub using the factory firmware.
So give them a try. Check the
One-Click Install Packages for KOReader & Plato thread for a packaged installer for KFMON and NickelMenu plus KOReader and/or Plato.