To be fair I think the industry's fastest response times refers to the speed in which they ship patches to fix security issues rather than rendering speed etc.
Yeah, usually Firefox will have a patch out within a day or two for 0-day exploits. Very fast response time. Apple and Microsoft take much longer for 0-day exploits.
Firefox's update system is practically flawless as well. It is rare for someone to have an out-of-date version of Firefox or extension.