Due to the special circumstances though (I like my KDE 3.5 desktop and although I am thrilled by KDE4, I am still unconvinced it’s ready for everyday use) what I did was to download the KDE Live ISO image, and I install it on my USB stick using this script by katzj which also allows you to save data on the USB stick (allows persistence).
So, I’ll test it and decide if I’ll move into KDE4 or stick with Werewolf till Fedora 10.