Firefox

Yes. I sync everything but passwords and bookmarks.

Nah, I dont use it. In fact, I go through and disable almost all the "extra" stuff in any browser I install. I'm of the "Do one thing well" school of thought, so all these apps trying to do everything, all at once, just to keep you in "their" system? No thanks. Sync offers absolutely zero features that don't have better, alternative options already.

Yes. I want to have access to both history and bookmarks on all my devices and send specific tabs to other devices. Sync makes these super convenient.

Yes, but only on new installs to get all my extensions and settings. Then I disable it

mostly just to send websites I find while on mobile to my PC so I can properly read/interact with them on my PC

Yes, but it doesn’t synchronize all like the values in the about:config.

No, I use my devices for different purposes and I don't have any interest in them communicating

No, I don't need yet another account, nor do I have a need to sync anything.

I don't really use bookmarks, and haven't found much value in sharing anything between my devices. I just install ublock on new devices and that's about it.

Yes, because it helps me organize my horde of bookmarks that I need to sort and keep on task with my projects.

I sync bookmarks between devices and sometimes send a tab from one device to another.

EDIT: I trust Mozilla way more than Google.

I wouldn't have it any other way. I need to have my desktop and phone browsers synced.

I use it for open tabs only. I then monthly bookmark all of them on a desktop. Then I close all the tabs on my phone and start again.

I use it for preferences and bookmarks and stuff. But I never save passwords in any browser, I have my password manager for that.

No. I tried it once and lost half my tabs and bookmarks. I assume because they were different on each device I synced. One overwrote the other. Maybe if I had brought an in-use device into a new browser installation it would have worked as intended. But I don't trust it won't lose things now. All my devices have their own set of things to sync.

Yes, I trust the encryption layer and the Mozilla Foundation has good ethical principles. I'm also a big fan of Firefox Relay (email alias provider) to protect my inbox from spam.

using it, syncing my bookmarks with it between systems (work, home, laptop, phone, tablet)

Yep. It's e2e encrypted, and you can even self-host the sync server, if you don't want to rely on an external service. Pretty much a no-brainer.

Yes. Because I have too many devices. Firefox sync is easy except that I have to reconfigure settings for each add-on.