My experience is exactly the opposite. When forced to use Chromium on Linux, I find it slow. The dev tools are lacking basic functionality that I came to depend on, and they are unreliable (missing requests in Network tab). When testing CSP protections about a year ago, Chromium allowed many of the requests that should have been blocked (and were, in Firefox).

I think it comes down to what one is used to. We probably learn to sidestep problems with any browser we use, but using a different browser inevitably leads to frustration.

Of course, this is not true if you are using Google services. Google seems to put an extra effort in making sure that their pages are as slow as possible in Firefox... I don't care much myself as I don't use them, but it's a good reminder of how (non)non-evil they have become.