I'm happy to report that all went smoothly. The installation process gives the option of retaining your existing version of Office. 2007 is very different from earlier versions and it could take a little while to get used to the navigation. There's an awful lot of taskbar clutter that needs customizing out but that was the same with 2002. The Edit selection is nothing like I'm used to and introduces triple-clicking and watching the mouse arrow change orientation to select text to copy, for example.
Looks interesting enough to keep. Give it a go!