I could be alone here...
I know you can fanangle a user.js file to flip a heap of about:config settings, but I would like to be able to use the registry too. This is because it can be difficult to automate settings, eg finding the FF profile and checking for existing lines in the user.js file. I think the user also has to open FF at least once to generate the profile folder?
There's other reasons as well - I can't remember them all.
Thoughts?