Firefox Quantum seems pretty awesome so far. Major kudos to Mozilla for doing what amounted to swapping out the engines, wings, and cockpit of a carrier jet while it was still in flight. They landed this bird well.
Firefox and Opera will always be welcome at my table. Not only because I'm against browser monocultures, but because Mozilla's work for the web cannot be understated. I'm glad they finally have a competitive browser and I hope that Firefox is able to stick around for years to come.
That said, my personal browser of choice will remain Chrome, up until the day another browser becomes so good that it's clearly far better in the majority of my use cases.