Absolutely. When I first starting using FF and all the developer tools, it would grind to a halt. Now that I'm a lot more comfortable with the FF toolset, I have a minimal set of extensions and it feels much snappier.

I also use Aurora which is still super fast to me. I also develop with Chrome Canary and the stable Chrome version. Canary has times when its totally useless or when someone breaks the build and I can't use it for a week so until the next update comes out.

All in all, yes, less overhead means a snappier browser to me.