I mean, maybe for you. But for me, with the add-on that I use, and the computer that I am on, FF is not the most optimal, Chrome is. FF is slower for me and my set-up.

EDIT: I'm not joshing here or trying to trash on others. FF may be faster for you, that's fine. But in my own personal little corner of the world, FF is slower than Chrome. I've no idea why, maybe I could spend a few days trying to figure this out and then optimize FF to make it faster. But, for me, out of the box, FF really is slower.