why should I upgrade to 7.0.1

The newest version always is better in performance, security, interface etc.

see: http://www.mozilla.org/en-US/firefox/features/

Always FIREFOX is a freeware. No cost at all.

thank you

My situation is on the other side of issue. I DO NOT want to upgrade to Firefox 7.0.1. I already tried it.

MOST of the Add-ons are NOT COMPATABLE with Firefox 7.0.1.
I uninstalled firefox7.0.1 & went back to Firefox 5.0, which seems to be working  better than firefox 7.0.1 did.
 I am running Windows 7 Home Premium & do not have Internet Explorer installed & do not miss it.
 I need Firefox, for  I have very low vision & IE is an insult to those who do not see well. 

ps. the bold print here ,was not initiated by me, so don't take it to mean that I am yelling at anyone. Thanks, very much.