Honestly, recently I've consistently noticed Firefox running faster than Chrome for my usage scenario. It might be bias, but I find browsing on Firefox a more enjoyable experience and uses a lot less of my system resources.
I stuck with Firefox through the times where it was much slower than Chrome for idealistic reasons as well, but now I feel like speed is less of an issue because they are both pretty even.
It might be a placebo effect, but I find that I switch back and forth between Chrome and Firefox every 6-12 months after the one I'm using feels slow and the other feels faster. Maybe they're actually leapfrogging each other in performance, maybe not. I'm currently on my Chrome phase.
I stuck with Firefox through the times where it was much slower than Chrome for idealistic reasons as well, but now I feel like speed is less of an issue because they are both pretty even.