Great pr, but Quantum sounds like they finally ported some of chrome 1's tech over. It's great that they're multiprocess now, but it seems more like they've caught up after 9 years, not like they're ahead much. And the UI is still off on macOS.
But Mozilla has been optimizing around this technical cruft for so long now that not having this technical cruft anymore leaves them with the architecture of Chrome plus those optimizations.
And they are innovating on top of it as well. They packed in a written-from-scratch CSS engine into this release, which utilizes parallelism. That's something we haven't yet seen in other browsers.
In a few releases from now, we should also get WebRender, which essentially makes it so that Firefox renders webpages in the way that video games render things. So, if you've ever wondered why your graphics card can pump out cinematic space battles at 60 FPS, but your browsers stutters when playing a flimsy CSS animation, this will mostly fix that.