It really depends. I mainly use Firefox, as I love the customization, however, I like Chrome becaus it's faster. But for some reason, a lot of sites refuse to load for me on Chrome. I'd use Chrome as my primary browser if I could get around that, as I love how many tabs I can have open and how clean watching videos is. Whenever I try to watch a 720p 60 FPS video on firefox it stutters a lot.
TL;DR:
Firefox is bae.