I used to use Firefox and I'd love to use it again on both desktop and mobile, but it's just so slow, memory-hungry and crashy compared to Chrome.
For example, I work on a wasm project in my spare time and it loads in a few seconds in Chrome. It does so, too, in Firefox, but just the first time. Reloading the page causes Firefox to leak a ton of memory and compiling my wasm suddenly takes dozens of seconds before crashing. And this is just a random anecdote, of course, but it's one of many over the years.
For example, I work on a wasm project in my spare time and it loads in a few seconds in Chrome. It does so, too, in Firefox, but just the first time. Reloading the page causes Firefox to leak a ton of memory and compiling my wasm suddenly takes dozens of seconds before crashing. And this is just a random anecdote, of course, but it's one of many over the years.