I think the quality and variety of styles is the strength of the BK7m. It also has good lead sounds, at least the ones I use.
Drums and bass, in my opinion, are better than Tyros and PA3X.
Biggest drawback is access to controls. Many things are hidden in menus.
Also, it does not display text files for lyrics, and lyrics imbedded in midi files are only displayed on external screen.
I have 50 commands I can call up from my controller keyboard though, including direct access to endings, intros, variations, break/mute, sounds, performances, etc. You can do things via controller that you can't do directly on the module, such as one button push for, for example, intro 2, or ending 3. Two pushes are necessary on the module.
If you want to put in the homework, it makes a really good arranger.
DonM