Firefox rocks my world for all those reasons and more.
Hell, I would use it just for the Tree-Style Tabs addon, which isn't available for Chrome.
But I use Chrome at least as often as Firefox for one reason alone: when everything doesn't go smoothly and a page does crash, it doesn't take the whole browser down with it.
When Firefox hangs and/or crashes, it's much more annoying because everything is interrupted to a greater degree.
Chrome: Oops! This tab crashed, just reload it or close it and move on.
Firefox: Firefox has encountered an error and must be closed. Do you wish to debug?
As someone who spends a third of the day on the web professionally, and always has 10-50 tabs open, it matters.
Thankfully, plugins made it into their own processes a while ago, which has greatly reduced the number of crashes.
That said, per-tab multi-process is coming as part of Electrolysis: https://wiki.mozilla.org/Electrolysis
You can follow along the roadmap here: https://wiki.mozilla.org/Electrolysis/Roadmap
It's already available in Nightly builds just disabled by default. If you'd like to try out a Nightly on Windows without messing with your local copy of Firefox, grab a copy of Firefox Portable Nightly and it'll run with it's own separate profile and Firefox install without affecting your local one: http://portableapps.com/apps/internet/firefox_portable/test#...
https://wiki.mozilla.org/Electrolysis
I believe you can enable it right now in about:config (browser.tabs.remote), but it's not production-quality yet.
On my x86_64 linux system, Firefox is marginally faster at Mozilla's Kraken benchmark (a few %), and Chrome is much faster at Google's Octane benchmark (30+%).
There's a reason why I keep going back to Chrome after trying each version of Firefox for a week or two, and it's all related to basic user experience: performance and stability.
I don't know about today, but a few years back starting up Firefox was painfully slow, and when an update arrived it would first nag you about it and then during restart started checking for extension compatibilies. Even using felt sluggish and was temporarily fixed by running the sqlite vacuum in it db.
Chrome for whatever reason had none these issues, and it felt even slightly nicer to use, with usability enhancements all around like more fluid animations in tab moving, and all settings on a nicely laid out web view instead of a tiny modeless window with 10 tabs.
I really hope Firefox can not just catch up, but go past Chrome. Unfortunately the last time I tried it not too long ago, it didn't start but instead wanted to show that it is checking for extension compatibilies. Didn't exactly fill me with excitement.
http://secunia.com/vulnerability-review/browser_security.htm...