I've taken a long time to get there, but Google Chrome is becoming my standard browser. Not because of its blazing speed, or because it works so well with Google Apps, though both things are true and wonderful. It's really simple:
It starts quickly.
To explain: If I was someone that started an instance of Firefox at the beginning of a session and left it running, I'd stay with Firefox - it's great, it's easily fast enough, and it has great plugins and extensions. However, I don't do that - I run lots of complex apps in the browser now, my laptop runs for weeks without a full reboot which seems to be more than any browser can manage, and I have a stack of physical and virtual machines on my home network that I access all the time.
In all cases, when I hit the icon to start the browser, the clock is running and I get very impatient. Chrome starts incredibly quickly, it's like an old school browser. I don't know how they've done it, but I find that I can't do without it. Firefox always took a long time to start, even on my wonderful speedy laptop, but that wait seems unbearable now.
The effect is even more obvious on slower machines. Most of my virtual machines have limited memory, and it can take 30 seconds for Firefox to start. That's unacceptable; if a Microsoft application did that, it would be ridiculed. Chrome takes a few seconds at most, and I love it.
I think Firefox is reaching that stage in life where it is going to need some kind of precaching application that runs at system startup. Its precursor got there too, and where is the full-on Mozilla now? Something needs to be done. As much as I like Google products, I don't want them to own everything.
Handily, just as I write a glowingly positive blog entry, my Chrome started playing up. It now intermittently crashes on Gmail startup, and is subject to random hangs.
I am on the dev channel, so I have no real right to complain. It's annoying, is all.