Honestly, every bug/glitch/criticism is important, even if it doesn't affect a large portion of users. Ideally, it should be reported in Mozilla's bug tracker if it hasn't already, but still important nonetheless.
You keep bringing up this point about feedback that is irrelevant to the actual conversation at hand. Nitpicking feedback is kind of useless and pedantic when the purpose isn't to be feedback.
The comparison app (Chrome) _just works.__
Firefox has gaps for a noticeable fraction of folks.
No one complains when their software works as expected.
[Edit] I say this as someone who prefers firefox on all their machines wherever possible.
Except when it doesn't. I initially switched to Firefox on Android because Chrome was crashing often and was noticeably slower.
For example, how do we know my good experience and your bad experience are not easily explained by hardware differences? If so, what does that say?