I've tested Firefox's performance recently and it's gotten super close to Blink/V8 in terms of performance, it even works better than those on my machine.

Same. In fact, I originally switched back to Firefox on my personal machine specifically because Chrome was making my laptop sound like an airplane taking off, even with only a single tab open. After the switch, I was able to open multiple tabs and even run other programs at the same time without a problem.

Come for the speed, stay for the privacy.