Drifting further off topic but just noting tht I have got round to reading the content of Mark's link above.
It does look very interesting and quite capable... I don't know Lisp but it looks to me should be relatively easy to learn how to use this program and there seems to be suggestions of producing graphical user interface at some point in the future which will make it far more appealing.
I intend to try to get it running on Linux at home sometime this week and look forward to seeing if I can use it.
I have to make it clear that I am far from expert at music software but my own feelings do tell me this one is well worth investigating and perhaps following the development.