For what it’s worth Ralph, I jumped in on a home machine. So far so good! 
You could always try a portable version to see how you like it first:
Mozilla Firefox, Portable Edition | PortableApps.com - Portable software for USB, portable and cloud drives
upgraded to FF5 some weeks ago, so far so good,
to me it’s to early to jump on FF6 version.
The problem is with the extensions since some needs updating too to keep up. This is why I still have Firefox 3 running alongside 7. Chrome is now my primary browser but most of my add ons are still on FireFox 3. I prefer Chrome to be light without any extensions. I will only move up on Firefox when I have tested that my extensions are working. Multiple firefox versions are easy to do, just by having multiple profiles (appdata).
Mozilla Fire fox 6 seems like Mozilla 5, there is no major change in Mozilla latest version.