The installation process is pretty ordinary. The eye candy is a nice touch. I just want to point a couple things out.
Anywhere in the instructions where it talks about removing the hardware key, ignore it. (Leave the key in.)
It doesn't matter whether you do the key update or the installation first. Obviously 9 won't actually run until you do the update.
You can do 'Typical' installation. The 'Custom' option doesn't allow enough customization anymore, so skip it.
The default install location is now Applications -> Graphisoft, rather than Applications. I'm leaving it there.
I think desktop shortcuts are stupid. If you agree, remember to uncheck the boxes about them at the end of the install. Dock shortcuts are naturally superior.
The documentation PDFs don't install automatically. After the installation finishes, copy the 'Graphisoft Documentation' folder from the CD to the new Archicad 9 folder, within Applications -> Graphisoft. Change the name to simply 'Documentation', or the docs won't show up in the help menu.
The first time you open AC9 it will look weird until you fix your Work Environment.