why bother with any Sony software
sigil for editing
ADE for previewing - how it looks in ADE is how it will look on sony
calibre for library management & sideloading & shopping links
All Sony software -> nearest bin
no need to shop via Sony - anywhere that sells or offers free epub will do
+ Sigil, ADE, Calibre all play nicely together. you can hot key open a book in either of ADE, Sigil direct from calibre main window