I'm using it, it seems to work fine, and works/syncs on mobile as well (mobile Firefox that is, not for other apps AFAIK), and on my work computer's Firefox ins

I'm using it, it seems to work fine, and works/syncs on mobile as well (mobile Firefox that is, not for other apps AFAIK), and on my work computer's Firefox instance. I seem to recall attempting to change my Firefox sync password once and it notified my that I would need to export and re-import the passwords (IIRC), which I took to mean they are careful to never get full access to them unencrypted on their side. While less convenient, I like how that's set up if it's how I think it is. For every device I have logged in with Firefox sync it just works as you would expect.