Up until the 2010 version, I would have said PrintMusic. However, the 2010 version of Songwriter has had a lot of the missing abilities added back in. Now, I see no reason that SW won't do barbershop arrangements just as well as PM.
PrintMusic 2004, 2006, 2008, 2009, 2010, 2011; Finale 2010b, 2011b, 2012c, 2014
Mac OS 10.9, Windows 2000, Windows XP