Benchmarks are not everything. Firefox feels sluggish and less responsibe when scrolling, switching between tabs, on startup and just in general.
This might not be the case one every machine, I don't know, but it's been consistently true for my usage, it just doesn't feel right.
Unlike the new Opera I might add, it provides a really great experience. The fact that you can now install chrome plugins did it for me as I was a vimium addict. I think the move to blink was the right move for them.
I believe that there are two things being discussed here. One is performance. The other is reactivity.
Performance (aka throughput) measures the total duration of operations, e.g. how long does it take to display a page once it is loaded, how fast a script will be executed, etc. When Chrome was introduced, its performance was much greater than Firefox, largely due to v8. Some other factors involved were add-ons (it used to be really easy to write Firefox add-ons that kill performance, and it used to be impossible in Chrome), or old bloated profiles (which of course didn't exist in Chrome). Now, after lots of hard work, the Mozilla community has managed to make Firefox faster than Chrome. That's what is measured by benchmarks, and that's one point for Firefox. Simultaneously (and this doesn't appear in benchmarks) the Chrome add-on and profile situation have started to show the same weaknesses as Firefox'.
Reactivity (aka snappiness) measures how fast an application appears to be, i.e. the total duration of user-visible pauses, e.g. how long does it take to switch between tabs, or how much one tab eating all CPU affects other tabs. When Chrome was introduced, its reactivity was also much greater than Firefox, largely due to the multi-process architecture. Some other factors involved were add-ons, once again, or old bloated profile, or simply the fact that the Mozilla culture initially didn't take into account this factor. It took some time for the Mozilla community to realize that reactivity was just as important as speed. After lots of hard work, the Mozilla community has managed to make Firefox... well, much better than it used to be. Improvements include off main thread rendering, off main thread disk I/O, asynchronous add-ons, etc. Unfortunately, desktop Firefox does not have multi-process architecture yet. This gives a considerable advantage to Chrome in this domain.
Work is ongoing to bring this multi-process architecture to Firefox desktop. The task is long and difficult and might, unfortunately, kill a number add-ons, but I am confident that the Mozilla community will achieve it.
Incidentally, FirefoxOS has a multi-process architecture already.
Caveat: I'm a Mozillian, and I'm involved in Reactivity work in Firefox.
Perhaps the "long and difficult" multi-process architecture will be the ultimate fix, but it'd be great in the meantime to get some tiny hint about which tabs are sucking up memory/cycles. This could be very crude - a count of the tab's timeout-firings, object allocations or whatever - and it would still allow significant self-help.
For memory, you can already look at about:memory.
For performance, if you are running Nightly, you can use the Gecko profiler that basically tells you everything about what takes time. Note that, by design, the Gecko profiler is activated only on Nightly releases.
But yes, both features are rather hardcore. We are working on more user-friendly solutions, too, although I have no idea of the roadmap.
For what it's worth, the multi-process architecture is designed to customize from one-process-for-all-tabs (plus one for the ui and one for Flash) to one-process-per-tab. I don't know whether this will be a released feature, though.
While we're talking about what "feels snappier," why hasn't anyone mentioned Safari. It is, by far, the smoothest browser on my computer. It may not do as well as Chrome in the benchmarks, but the scrolling is a thousand times smoother and everything feels quicker.
This might not be the case one every machine, I don't know, but it's been consistently true for my usage, it just doesn't feel right.
Unlike the new Opera I might add, it provides a really great experience. The fact that you can now install chrome plugins did it for me as I was a vimium addict. I think the move to blink was the right move for them.