It's an excellent program. It's very expensive though. For most purposes, one of the cheaper Finale or Cakewalk (or any other notation program like Musicease or Sibelius) will work fine, but if you feel the need for a full professional music notation program, you can't go wrong with Finale.

When buying "cheap" software on ebay be aware that you may be purchasing illegal copies. For instance, could this Sibelius http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=270022664449 really be genuine - I didnt buy it because I assumed it wasnt.

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Incidentally, I find Finale 2006 terribly idosyncratic and its GUI fails to properly comply with Windows conventions. In that respect Sibelius is better but every-one has their favourite software - often for reasons which may not be relevant to others!