I mainly use Chrome (technically Chromium) when developing web pages, but I verify functionality works with Firefox. While the built-in developer tools are about equal, in Chrome it's much easier to enable/disable request logging. In Firefox you have to jump to a different settings pane which is a pain.
However, I use Firefox for non-development because it uses less RAM, and at the time (a few years ago) Adblock Plus blocked ads in Firefox before the page loaded, but in Chrome it only blocked them after the page loaded. I use uBlock Origin with Firefox now, but adblocking may have improved with Chrome since I last tested it.