Sorry, i haven't gone there yet
i was working on Maverick last year,
then got put on a newer iMac with Yosemite, and i haven been loving my FCP experience.
not terrible, but a couple of little bugs that are annoying
(they may have been there under Mavericks, too, i just hadn't gotten far enough into the project to notice)
i understand that CinemaTools is completely broken under El Capitain,
there are however a couple of tools that can replace it's useful "Conform" feature.
i can't really compare my Mavericks/Yosemite experience with Mountain Lion, as they were never on these machines.
these machines do open and re-start much quicker than my older Mountain Lion laptop, (for what that's worth)
nick