Almost perfect, two tweaks would give it 5 stars.

This is a great program for converting books.
The only things missing are multicore support (if youve seen XLD ripping / compressing a CD youll know what I mean) and a counter for number of audiodisks currently ripped (sometimes a CD will be ejected by OSX and if unattended youll never know you missed a disk)
That said, excellent program.

BlueBillCanada about Audiobook Builder, v1.5.3