On my laptop and desktop (Win 7 machines), I use FF 15. That was the last version that seemed to have less conflicts and problems. Mozilla’s rapid release is crap.
I also occasionally use their FF portable at version 23.
FF has become bloatware and caused more conflicts than it resolved. I had trouble with some versions and Adobe Flash, PDF files, etc.
FF has become more of a hassle than it is worth. It used to be a great browser.
Agreed—it’ll be interesting to see it they get any flack over this.
I tried to stay with FF15 but I found that many of my plugins wouldn’t work anymore. I use FF25 but that’s as far as I go. FF26 changed too many things and I refuse to upgrade any further.