Firefox

No. Not for any good reason though... I just don't need it.

Firstly, I use LibreWolf rather than Firefox. It still has Sync but it's disabled by default and I've just never felt any interest in enabling it.

I use KeepassXC for passwords, so I don't need Firefox to sync those.

I don't use bookmarks. I don't have an amazing memory or whatever I've just always found it more convenient to just search for whatever I'm trying to find, whether that's searching my history or google or whatever. Like how do you organise bookmarks? Trying to categorise pages that I may wish to refer to in the future would drive me nuts. I do use Zotero which is similar to bookmarks but only for academic research.

Even transferring things between devices. That might be nice but seriously I just search for whatever it was I was looking at on whatever other device.

All that remains is addons and themes and honestly it's kinda nice to start with a clean slate on every new desktop and add in themes and addons. Only takes a minute.

I use it, but when I experimented with data synchronization using Firefox Sync, it simply doesn't work, it is so unreliable and unpredictable that you can't bet on it. It's a real pity, because I wanted to use it for a cool thing, synchronizing data of one website, without having my own server for that website. It failed because Firefox Sync fails.

It's a great way to set up Firefox on a new device. Why wouldn't I want to install the same extensions and copy my bookmarks? I wish it also synced toolbar layout so I wouldn't have to remove those weird spacers Firefox adds around the address bar by default every time

No, because the set up page for it has never actually loaded for me. Ever

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.

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

I love Sync!

Except on iOS, where my bookmarks and passwords never actually synch, because it's not really Firefox but a weird skin on Safari because... Apple.

I tried it at two separate times, and both times it would delete my tabs when I add a new device to sync. Maybe I used it wrong, but it just aggravated me to disable it quickly.

Rarely, mostly due to accessing a cool website I found a few days ago on the device I am currently using

I used it accidentally. Now my work PC and my personal laptop have a mishmash of unwanted bookmarks on each

Nice try FBI...