I have used BIAB since days of floppy's and version 6.0. AS to simplicity, All you have to do is type in the chord changes and select the style to create a simple backing track. For complexity, the manual is only 518 pages. I still don't know how to use the more advanced features. It is a huge and very powerful program. The difference in packages is primarily the number and variety of real tracks in the package. The program also comes with a separate DAW called Real Band.

One of the biggest features is the website at pgmusic.com. It has a huge user base on the forum with the author of the program getting involved in answering some of the more complex features. Also they offer a no questions 30 day money back guarantee.

I personally can't imagine having to enter in every part of a basic arrangement to create a simple track!