After waiting for 6 moth, today (24/04) canonical released ubuntu linux distribution family for public.
I have a oppotunity to try it on first chance, download the ISO image here burning to DVD (one of bottle neck poblem if you burn more than 700 MB to CD), and try to fresh intall on my other pc.
about 1 hour installad dan configured it on my x86 machine, IMHO on Hardy heron you can't find big step from this release and Gusty Gibbon released except some improvement on easyly to configuration your xorg, new world clock applet, and other minor improvement.
maybe you will confused because they package firefox 3 beta version with still many bug on his own program. for kubuntu, i can't found KDE 4 as default session, this is still KDE 3.9.x
Overall, I think for compete with other OS. Ubuntu family need do some bug fixed and many improvement again.