well, I've been trying different options when fooling around with some ideas and melodies the last couple of days and things are clear for me: writing a song is best done behind a piano or keyboard. It allows me to slow down or stop, play a bar or sequens again or slightly different without any hassle. The styles of an arranger keyboard can give me an atmosphere and give an image of how a tune will sound (more or less).
When this writing phase is complete, then I can use a program like Sonar or Cubase to record my song. But this is production work, not songwriting.
BITB is not for me. I enjoy fooling around with the possibilities, but have no urge whatsoever to use it as a writing tool.
For songwriting the piano or keyboard is defenitely my favorite.
Thanks for the input everybody.
Joop