I jumped from MC15 to MC17, although it must be said there was no improvement in any of the audio processing, but I recall that the format is easier to use in 17. From what I can tell, the big improvements have been in the handling of video files. I asked the question on the interacr forum at the time, and never got a proper answer, which in itself probably is the answer. I've got no desire to jump to 18 at all.