My experience was that I first upgraded with archive and install, and it hung with the spinning ball from the village in the tv british show the prisoner, of death, after booting. So, I did a clean install and that worked.
But, it might have been the same problem I had later, which is that DiVX hangs on startup. So, maybe after upgrading, you could boot to single user mode (hold down cmd-s during boot) and remove (move away) /Library/QuickTime/DivX... and/or /Library/DivX...". and have it work.
There other thing I read about searching the web was people having Application Enchancer (APE) cause hanging. I didn't have that problem.
But a clean install was what I ultimately did and it worked for me.