It's honestly almost solid. On the first use each day, or maybe even each browser session (I haven't confirmed), it will ask you to punch in a 6-digit code to activate it. Since the 6 digit code is shown, I see no point in this - so it really could just be removed altogether. After all, I am already logged into iCloud, why do I need to "authenticate" this again? The window also seems to position itself on the top-right of the browser window, covering the input field which is mildly annoying but doesn't hinder your ability to enter the code. Once you're past this however, it's fine. It works as expected.

Works, but with issues.
First, it doesn't sync the passwords - it masks ones stored in Firefox with ones from iCloud.
Second, it introduces noticeable input lag to remote IDEs like RStudio.

It was a shame that the plugin did not work for a couple of months but now it is back and runs fine! Thank you very much for supporting Firefox!

werkt eigenlijk goed, maar soms is het een beetje vervelend met de hoeveelheid verificatiecodes. Het lijkt erop, dat de verificatiecode nodig lijkt, als ge uw Mac opnieuw start. Tenminste moet ik nu niet langer gebruik maken van Safari, en kan veilig en zoals geweend genieten, van het internet.

Add-on works as advertised, I don't know what everyone is complaining about. Maybe they don't know how add-ons work? Anyway, the most common complaint is they cant get it to stop auto filling. The solution: Goto Manage Extensions>choose icloud passwords>choose Preferences>uncheck In-Page Autofill.

Problem solved.

Want to use FF's own password autofill? Goto Manage Extensions>choose icloud passwords>choose Preferences>>uncheck Turn off Firefox Autofill

Dont want any autofill from either? Goto Manage Extensions>choose icloud passwords>choose Preferences>uncheck In-Page Autofill>check Turn off Firefox Autofill

Want to use both password managers? Goto Manage Extensions>choose icloud passwords>choose Preferences>check In-Page Autofill>uncheck Turn off Firefox Autofil

It's not that complicated, people. It's like dealing with children around here. Sheesh. It works. Firefoxes works. Roboform works. LastPass works. Just pick one or don't; I'm not your dad.

Entering system password for each use is a bit inconvenient.

dobra

It works pretty well but can slow down the browser on some sites depending on how many input fields are present in the DOM. It would be a huge help to be able prevent the extension from running on specific domains.

Apple developers - please add a persistent configuration option to prevent the extension from running on specific websites. Many extensions support this functionality. i.e. uBlock Origin and DuckDuckGo Privacy Essentials