Summertop: I would most definitely call it a downgrade rather than an upgrade. All you get at the moment are some additional restrictions and obscure "security advantages" which are so annoying that everybody will ignore them/ turn them off after a short while. This article ("20 Things you won't like about Windows Vista" may be a good start, although I wouldn't agree on some of his statements, especially on his "OS-Ranking". It definitely shows some disadvantages from the user's viewpoint.
Anyway: I have not heard of any reason to switch to Vista except its improved look&feel (which is IMHO inferior to the look&feel of other modern OSes like MacOS or up-to-date Linux distributions) so far.
(verberg) Als u op uw beurt aan het wachten bent en niet steeds op F5 wilt blijven drukken kunt u ook de pagina snel automatisch laten vernieuwen door op "Verander" naast "Verversen" te drukken op de Hoofdpagina, en de tijd hier in te stellen op bijvoorbeeld 30 seconden. (Servant) (laat alle tips zien)