I tried to switch over. Switched from chrome to firefox completely for about two weeks after quantum.
I got random high cpu usage from firefox. Some random pages just spiked the cpu and everything slowed down. Same thing on both my workstation and laptop.
I also didnt find a way to make opensearch working. In chrome i can just type part of the url of a website, press tab and write a search query and get a search on the website.
That is so worked into my daily routine. It just became an annoyance and a dealbreaker. :(
I really really want to switch. But chrome works really well and my browser is such an important tool for me so i really want to use the absolute best.
Its kind of a developers wet dream if you like that kind of stuff. :)