I found out about BIAB right here in these Sonar forums. After listening to some professional sounding productions of original music posted in the Songs Forum, I asked the songwriter, Guitarhacker, how he accomplished that. He explained his process which included audio tracks in BIAB which he edited and mixed in Sonar. I was hooked. As a singer-songwriter myself, I'd been searching for a way to produce my own music which is what lead me to Sonar in the first place.
I you click on the link in my signature and listen to any of the songs I've posted there, you're going to hear BIAB Real Tracks that were imported/edited/mixed/mastered in Sonar. There are a number of Sonar users in these forums using that same process. Cheating? Idk about that, but I do know that guitarist Brent Mason's killer leads are featured on a few of my songs, along with several other Nashville studio musicians.
Here's a link to a BIAB SoundCloud site featuring original songs uploaded by BIAB users:
https://soundcloud.com/bandinaboxradio