This isnt really true anymore. Firefox has caught up in devtools, and has superior tools when it comes to animation debugging. Performance also isn't worse than chrome, in fact I've found that FF uses a lot less memory than chrome does.
The only time I open chrome is to use an occasional WebApp that needs the Bluetooth API or something like that.
On my 2017 Ultrabook with only 4gb of ram, Firefox stalls repeatedly & has long stretches of being entirely unresponsive after half a dozen tabs, and gets worse from there.
I have some delay where a navigation might be delayed some, but Chrome doesn't ever lose input and generally manages to keep going.
Even on a desktop with 64GB ram, Firefox gets slow over time & needs to be restarted when I have a significant number of tabs open. Tab auto-suspend extensions generally "fix" the problem, but it's been frustrating that whatever the on-page performance is in Firefox, the app itself feels so prone to bouts of unresponsiveness.
Please be more precise about what you mean by "significant number of tabs", is it 50, 200, 500, more ?
Because on a 16 Gb laptop, I don't have any problem with 50 tabs open with Firefox.
The only time I open chrome is to use an occasional WebApp that needs the Bluetooth API or something like that.