Everyone in my company received a strongly worded email today from our IT guy warning to not download this upgrade. He advised of all the problems it could cause. It didn't mean much to me because I've been using Mozilla ever since I heard about it here on Free Republic a year ago. I haven't experienced any of the problems my co-workers constantly experience with IE, especially with the dang pop-ups.
I've been using Firefox for a little over three years and have had the same positive experience as you. When I first started using it, I would switch back and forth between it and Internet Explorer, then scan with anti-virus and anti-malware programs after using each browser. It was obvious to me that IE was not as secure as Firefox. Since then, malware has increased dramatically and I only use IE for Windows security updates. Then there's all the Firefox extensions that make so many things easier and more convenient than IE. I'm no tech expert, I just choose to use Firefox.
It looks like he was right. See my #205 and #207 on this thread. The guy in IT might be interested in seeing the MS web page links in those two posts.