I switched back to Firefox 54 from Chrome when multiprocess browsing ("Electrolysis") came out of beta. It's been absolutely great. It's fast and I trust and like the nonprofit behind it. And all the extensions I care about are available. My main issue with Chrome was the endless nags to sign in to a Google account, and just generally wanting less dependence on Google. I also like that Firefox has a built in tracking…
https://github.com/Eloston/ungoogled-chromium removes many of the nagging and background features related to Google services.
If staying free of Google becomes a goal, then by using Chrome you're still helping them, even if your Chrome is un-googlified.
This is because you help Chrome become a monopoly in the marketplace, I view it as the new Internet Explorer already. Many people here probably don't remember, but IExplorer also won on technical merits, version 5 being an excellent browser compared with its competition. Market dominance that allowed Microsoft to screw the web for a decade at least. And no, in this context its open source nature does not matter much for as long as Google controls its implementation and distribution.
Firefox is right now truly the best browser, at least for my usage patterns and needs, but even if it weren't, I would still use it, because when web standards are endangered due to a monopoly, then I consider it my duty to support the underdog.
Now don't get me wrong, it is true that Google and Chrome have helped the open web. But that doesn't matter that much, because they can always turn and you can see how lately Chrome is making bold changes without waiting confirmation from W3C or the other browser vendors — like disabling forms auto-complete or deprecating certificating pining.
They are at a point where Chrome has enough market share to implement whatever the heck they want. DRM? H.264? Lost battles after they ended up in Chrome.