If I were to decide against the BK9, it would be for these reasons alone:
1. No text display
2. No Vocal Harmonizer
These two things make it necessary to carry and hook up more peripheral gear.
3. That's about it actually. You can make it do about anything you like with a little work and ingenuity. For example, I'm looking at workarounds for lack of break/fill, and there are some.