Safari user here—I personally have never used extensions much (probably my own loss), and on Safari I just have 1Password and uBlock°.
Besides Safari's lack of extensions I find it to be more or less on par with Firefox, assuming you're in the Apple ecosystem. The dev tools feel extremely polished and feature complete. The only thing Safari's dev tools lack IMO is no fancy CSS support for things like grid or animations.
I occasional open up Firefox Dev Edition when I get a weird bug on a webpage and that sort of thing but besides that Safari has served all my needs perfectly.
>The dev tools feel extremely polished and feature complete.
Much less than that of Fx or Chrome. No support of extensions means I can't use something like https://github.com/vuejs/vue-devtools, no command menu, poor debugger, no performance\memory usage information etc. The list can go on and on. Safari's dev tools are about at the same level as they were in Chrome or Fx 5+ years ago.
As for the extensions part... well, not everybody needs them, I guess, but I can't really imagine my browser without at least, 1P, uBO, Stylys, Tempermonkey, TreeStyleTabs, Tab Session manager, Bloody Vikings! and All Mangas Reader.
Besides Safari's lack of extensions I find it to be more or less on par with Firefox, assuming you're in the Apple ecosystem. The dev tools feel extremely polished and feature complete. The only thing Safari's dev tools lack IMO is no fancy CSS support for things like grid or animations.
I occasional open up Firefox Dev Edition when I get a weird bug on a webpage and that sort of thing but besides that Safari has served all my needs perfectly.