Aside from using a dark theme for the default look of KDE how is it trying to be Vista? Any similarities it shows to Vista are just factors of them both being an OS in the year 2008.
6 months from now when KDE4 has matured some more you will be able to customise it to look exactly like ugly KDE3 if you like, as well as behave in the same way, and then what is there to stop you adopting it? If you cant see the benefits of the new underlining code in KDE4 then frankly you either don't know anything about KDE4 or are just in denial, it is an infinitely more powerful, more robust, more modern system (it just needs time to mature). Frankly it puts GNOME to shame in terms of the underlining technology.
But you know what is most ironic about your statement? I feel like KDE4 is the first time in years Linux has actually contributed anything new to the desktop. Stuff like there not being a desktop folder which is displayed on the desktop, but instead you embedded any number of folders as widgets, stuff that like is revolutionary and 5 years from now every other OS and desktop will have copied that feature.
I think the problem is:
A. People got burnt by a really buggy first release of KDE4 and they refuse to let it go and continue to have this grudge against it.
B. People hate change, and in the same way you read loads of idiots dissing Office 2007's interface even though it is clearly better than than Office 2003, you also get people dissing KDE4 for trying to improve things.
C. People seem to think it's cool to hate on KDE at the moment.