I use both, but my experience is different.

I use Firefox, for my trusted sites, mail, banking, various stores, documentation etc.

I use chrome, fore throwaway lookups etc.

Firefox runs for weeks at the time (I am on always on desktops (work and home)) (I restart firefox when new update hits.), but chrome gets laggy after few days.

And i am the type of person that has 100s of tabs open, over few windows each.

I do use primarily Linux though, if that makes any difference.