My newest article at macProVideo.com will tell you how to notate free rhythm in Sibelius 7. So please go to the macProVideo.com Hub and read for yourself!
Quite often when time is flying, it is necessary to create audio demos from your scores very quickly. You just don’t have the time to do a proper mockup in Logic or Cubase.
I have found combining exports of several notation applications to be a good compromise between speed and quality. See for yourself at macProVideo.com!