I think Mozilla have more relevance to web standards and technology now. As a web developer i have a slightly conflicted view of FireFox, i think Mozilla are great, because of MDN and the active community developing FireFox and fixing bugs... But unfortunately the browser just sucks in too many ways these days, there are fairly serious bugs that stay open for many years, they keep re-writing large chunks of the browser only to have it still act buggy and perform poorly, i have no idea why because their seem to be enough willing and skilled people working on the project.
IE11 ... while i hate it and want it to die, many parts of it perform significantly better than FireFox and are less buggy, but then it makes up for it by missing support for things that all other main browsers have and having an almost blanket ignore policy for bug reporting which is extremely frustrating...
MS have never once responded to any of my bug submissions. And I do not make vague bug submissions, i always give a detailed isolated examples. here's my experience among the leading browsers, basically reflects how i feel toward them too:
Chromium project responds frighteningly fast to bug reports and fixes fast, however they have a lot of regressions (especially since M39/40), probably a reflection of how fast moving it's development is.
FireFox responds fast to bug submission but usually fixes super slow, it's more likely with FireFox that a bug you discover will have already been submitted but have been open for years, i've discovered far fewer regression than chromium but some have been pretty stupid.
IE11/spartan/whatever MS rebrand their shit as Almost never responds to bug submissions or does and then closes and "will not fix", I've only found regressions between 11/10/9 but 11 feels almost completely stagnant, hardly feels like an evergreen browser at all.