How well does it work on iOS?

It integrates with the system password manager interface but it's sometimes a bit slow to start. I think the problem is that it updates the passwords every time it is opened instead of relying on cached copies. Other than that it works fine.

It doesn't integrate well with iOS but if you are willing to use Firefox for iOS over Mobile Safari, it works pretty well.

Firefox has been a great web browser for me, as the synced tabs over devices has been useful. And while Google still likely has some of my data, I've switched to DuckDuckGo and Firefox full time now.