I occasionally have Firefox freeze due to some site's script freezing, forcing me to end it through task manager as Firefox won't respond to any button clicks.
Also (unless I missed something) there's still no way to get hardware video acceleration on Firefox on Linux outside of Wayland. When I'm on Linux I'm also installing Chromium (with the VA-API patches applied) entirely for YouTube as my CPU usage ramps up immensely when watching videos. Watching videos in mpv (or equivalent software) is an alternative, but I like the convenience of watching videos directly through the browser.
Other than that though Firefox has been rock solid for me and has been my daily browser for years now.
I've notice a bit of this on Linux but it never bothered me, however, I feel like it's gotten considerably better lately. For example, I use to have to keep Twitch open in it's own browser instance or else the stream would become very low quality, or even die completely, when I went to another tab. That doesn't seem to be a problem anymore, but I don't know if it's anything FF did.
Also (unless I missed something) there's still no way to get hardware video acceleration on Firefox on Linux outside of Wayland. When I'm on Linux I'm also installing Chromium (with the VA-API patches applied) entirely for YouTube as my CPU usage ramps up immensely when watching videos. Watching videos in mpv (or equivalent software) is an alternative, but I like the convenience of watching videos directly through the browser.
Other than that though Firefox has been rock solid for me and has been my daily browser for years now.