I extensively make use of this profile feature. I create multiple profiles, based on my work.
- To create new firefox extension.
- To test the extensions.
- For office work.
Though I prefer using stumble to bookmark my favorite pages, for quick reference I store some on Firefox bookmark tool bar. When I tried with chrome, it had imported bookmarks randomly from one of the firefox profiles.
I feel the usability of browser increases with these add-on's, extensions.