I have a Soundcloud friend who uses Garage Band. Part of the issue she has is being new to music in general, and the other part is the learning curve of Garage Band.

Now, that as framework, let me say this. Everything she posts is dull, boring and unimaginitve. That is the inexperience speaking for the most part. She does what she knows how to do, which is usually finding some 4 bar chord progession loop and replicating it 2000 times, then writing melody and lyrics around that.

With Real Band, it's the opposite. You put in your chord progression, pick your style, and let it create. If you don't like it, regenerate and give it another shot.

The main difference between that A and B is that in the second scenario you have to know music well enough to know what a chord is and how progressions work. She doesn't know anything about "1-4-5" or "12 bar blues" yet.

Depending on your level of knowledge and general music concepts, BIAB/RB is the choice. There is a learning curve, but think about the fact that everything you do requires some time spent in that learning curve. That part is up to you. You can learn just enough to make the thing work, or as much as possible to make it work well.