Arranger keyboards are basicaly good at standard genres, (originaly arranger keybds were made for song writing)
Workstations are good in all genres, perfect in modern electronic music like Dance, trance etc...
of coarse, neither Arranger nor workstations are exelent in Rock, because Rock is for Guitars not keyboards...but electronic music is for keyboards...

In arranger keyboards the Song mostly depends on the manufacturer, in Workstations the song depends on the player.

i heard alot from arranger keyboard USERS that Workstations are not good at traditional music, this is the TRADITIONAL song i made on workstation keyboard : http://www.sendspace.com/file/bjfapa
it sounds pretty good to me, even better than on arranger keyboards, but of coarse as i said:In arranger keyboards the Song mostly depends on the manufacturer, in Workstations the song depends on the player.