My Firefox has become adware. Adware for Mozilla, but still: Every new tab I open, there is a “WE CARE FOR YOUR PRIVACY” message awaiting for me. Every restart, “LOOK AT HOW WE HAVE FEWER ADS, MORE PRIVACY”. And from time to time, if I don’t open a tab by myself, it will install Pocket and/or open two tabs at startup, one for the release notes and one for browsing, but still with the little mention “Firefox has been awarded the Firefox of the year by Firefox, thanks to how we don’t let the bad guys follow you with ads. Also please create an online profile so we upload all your passwords to the cloud. Because you’ll be safer.”
Honestly, Mozilla has lost the big picture. The whole point of it was to have fewer messages that occupy the mind and disrupt tasks, and Chrome does it better, as long as I’m logged in.
Also, in my mind, exchanging Chrome's insistence on Google logins is just the same as Firefox's insistence on their proprietary sync and pocket. I'll say no to every one of those things, because I do value my privacy and none of them provide proper self-hosted options.
Sync is optional, and you can use a custom server and self host it.
Last I checked, self-hosted Firefox sync uses Python 2.7, with dead GitHub activity. Not quite the best state for Firefox sync.