1) Firefox has an inbuilt updater that doesn't run in the background as googleupdate.exe does, regardless of Chrome being on or off.
2) Firefox has a larger collection of- and in general has better add-ons.
3) Support Mozilla to counter Google's increasing monopoly on all things mainstream e-usage.
4) Firefox is still entirely based on non-propriety open source ideology. Chrome and Google is not.
5) Counter the hipster movement of Googleism.
I personally moved to chrome (from Firefox) out of necessity.
I run 64bit W7 and I keep a Lot of tabs open and Firefox kept CRASHING. Call it flash's fault or a maybe a diff plugin or whatever u want, but I'm a pc tech and I did all the things that anyone with a brain would do to get it right and nada...kept on being BS. So, I switched.
The only I don't like about Chrome is that the tabs don't scroll; they simply get smaller and smaller. If I could change it, I'd actually prefer to use Opera's style of tabs; where they have an Areo like preview.
That being said, Google Chrome is about as stable a browser I've found and that counts for a lot.
I'll add a sixth which is a packaged installer in one of the leading free anti-virus programs. Avast has a huge market share and with every install their is a high number of those installing chrome. Many don't unclick the optional install thus many systems have 2 or more browsers.
i don't think those reasons really apply especially to normal users..
i was using ff before chrome. when chrome came out, i was immediately using it all the time due to it's speed and awesome simple interface. it didn't matter if it wasn't compatible, we surf popular websites.
i visit THG and anandtech all the time for tech but browser tech didn't matter to me.
there's not much mozilla can do against the heavyweights. they still did a good job.
I think the biggest factor is the UI change. I like many others hate the new UI. Many people don't want to have to muck around with customization options. Nobody I know wanted to use the new UI and prefer the IE style of previous versions. I'm still using Firefox as my daily browser, but I had to spend time customizing everything so it was how I had wanted it. To look and feel like 3.6 and some other tweaks.
Many people do not like change. Having to relearn a UI for something you have been using for years can completely turn people away. For Mozilla to change the UI to look like a Chrome clone was a bad idea and a step in the wrong direction. It feels more complicated than it is and has the feeling that everything is hidden despite only being a few clicks away.
I think ultimately the drastic UI change will hurt Mozilla and Firefox even more in the future. What good is having tons of great features if nobody wants to use your browser because of the look, feel and way you interact with it?
I've used Firefox for years, but it's become large and bloated. It's a memory hog that bogs down my system, I finally switched to Chrome which seems to do better. I'm happy to give FF another chance, but for day to day casual use it needs to clean up its act to be worth it. Not all plug ins exist in Chrome yet, but enough to make it perfectly viable and workable for day to day web browsing.
Hipster movement, hah. Take a good look at Apple fool. I was a loyal Mozilla user for years and before Firefox was born even. But sometime over the past couple of years I switched over. FF has just become too bloated and slow. Furthermore almost every google product is superior to competition. We saw Microsoft as holding a monopoly for a long time and frankly I'm glad to see it taken from them at least in this area, go Google, always remember, don't be evil.