This is a sad rant :(
I love Firefox (and Mozilla too) and have never switched to . Although I use Chrome for development. But few days ago I switched to Opera, because new Firefox’s (aka Quantum) CPU usage is insane.
Disabling extensions didn’t help, it just hogs all available resources. MacOS is giving me “Service Battery” warning when Firefox is running. And battery last about four times(!) shorter.
So I checked my options, and decided to go with Opera. One of my favorite features in Firefox, tabs on the side, is not supported in Chrome and Safari, so only decent browser left was Opera.
If they haven’t hyped it so much, I probably wouldn’t be writing this. But they raised my expectations, how much faster and better it is, how they finally caught up… and it is bad, like really bad. I’ve tried both beta and developer editions some time ago, and fans were going crazy, CPU usage was going through the roof, battery drainage… But I hoped that it will get resolved before they release a stable version.
I’m really sad, but if they don’t fix this I won’t be switching back to Firefox. Still, I’m going to continue supporting and donating to Mozilla. On the plus side, MDN is one of the best sites for web development resources.
Edit 02. Decemeber 2017
It seems that guys from Mozilla are aware of it and that they are trying to fix it. Hooray!
Edit 02. July 2018
Good news! It seems that Firefox team addressed the issue in version 61. It is still not perfect but way better than it used to be, so I switched back to Firefox!