I tried Pentadactyl and Vimperator before settling on qutebrowser. It's just fantastic and worth checking out if you're in the market for a keyboard-driven browser.
I'm on pentadactyl and loving it, but haven't heard of qutebrowser - what made qutebrowser stand out for you, if you don't mind me asking?
What got me to make the switch was that it wasn't Firefox. I got so fed up with Mozilla's bullshit that I went looking for anything else, especially after they broke all of my custom addons. Qutebrowser ended up pleasantly surprising me.