Originally Posted by karl1c

Another vote for KyBook 3. :-)

KyBook, KyBook 2, & KyBook 3 are all by the same author. KyBook & KyBook 2 are being phased out, so I'd start with KyBook 3 if I were you.

I'm currently working on a plugin for Calibre to sync to KyBook 3. It should be available shortly.