The fact that Realband will indeed replace Cubase (for pretty much all intents and purposes) and is included free, makes me tend to agree; if you learn RB you'll probably drop both the other programs. Try it, you just might learn to like it.

It generates backing (much like BiaB) and allows multiple audio ports, mulitple VSTi synths, etc ... and you already have it! The graphics may not be as purty as Cubase, but I have yet to ever be able to see those graphics while listening to a finished CD project.

I do not work here, but the benefits are still awesome
Make your sound your own!