KDE 4.1 is made entirely of delicious eye candy. It’s still slightly unfinished and geeky, but remains deeply tasty. As I say that “KDE is like Windows but it works,” so KDE 4.1 is like Vista but it works. Which is a bit like “KDE is like anthrax but not bad for you,” but anyway.
If you’re not willing to geekily beat it into behaving, don’t try it yet. But if you are: how to set it up in Ubuntu Hardy (you have to add an experimental repository); install gtk-qt-engine-kde4 to solve the Fugly Firefox problem; install quick launch if you want that (though I couldn’t get it to work); switch off single-click launch in Konqueror; reboot; fiddle with all the settings. Play and have fun.