I have skied the 2002, 2004 and 2005. I actually am kind of partial to the 2002 model I have. The frequency tuning top sheet was added in 2003 and I believe that 2003, 2004 and 2005 are substantially similar to each other. Perhaps there was some tweaking of sidecut but I think they are essentially the same ski.
Fischer rep told me yesterday that the sidecut has changed (it seems to enter the turn more cleanly now, according to him) but other than that, the ski is essentially unchanged, as Kestner9 noted. Which means, it is probably a pretty darn good ski! I liked mine for freeskiing as well as running gates.