Best Book Formatting Software?

Greetings,

For those of you who have used book formatting software to do your own formatting,

1) What have you used? and

2)What has your experience been like? - the good and the bad?

I am considering learning to do my own formatting or good-ish formatting that I can hand off to a pro to touch up. I have looked at Atticus and Vellum.

Any thoughts or wisdom from the group would be awesome.

Thanks!

Matt