I've tried 0.9 and 0.9.1 and 0.9 was okay though a little buggy, so I went back to 0.8. (0.9.1 wouldn't even start, though it was running in the task manager). Don't let me scare anyone away, though. What works for some might not for others, so this page has links to older versions.
You can change the theme (skin) and add extensions to get Firefox to do things it doesn't come "out of the box" with. Firefox isn't bloated with code, offering features you may or may not want, so that's where extensions come in. I highly recommend "IE View" for the times you might need to use IE.
I think this backup program is an absolute must, and especially for the newbies to Mozilla, like me.
Last but not least, here's a forum dedicated to Mozilla users, likely the best place to post with problems. The very first section, "User Support" is open, meaning you don't have to register.
(Special thanks to Toto27).
Have you used Mozilla and, if you have, how does it compare to Firefox?
Thanks for your help!
Addenda: Here's a couple of other themes and extension pages:
http://texturizer.net/firefox/themes/
http://texturizer.net/firefox/extensions/
And here's a "frequently asked questions" page:
http://texturizer.net/firefox/faq.html