I did, a few months ago when they disabled uBlock on my Chrome.

The experience has been a delight. It runs smoothly, I can customize it more than Chrome (compact mode being one example [1]), and with the official iCloud Passwords extension I get to use the same password manager I use on my iPhone.

I don’t think I’ll ever go back. Best part being, if I need something that Chrome provides and Firefox doesn’t, I can potentially implement it myself, and contribute to a proper open source project while I’m at it.

1: https://support.mozilla.org/en-US/kb/compact-mode-workaround...