Like just about any new feature, there seem to be major bugs in the new Password thing. After supposedly setting it up properly for Firefox, including deleting the browser's saved passwords and removing permission for Firefox to save new entries, on only one occasion did it properly provide a good new password. And the box where it offers to do so often won't permit any entry, but instead shows a number in a circle -- on one occasion it actually changed my user-name instead of the password.
After a few hours the Password icon mysteriously disappeared from the Firefox toolbar and I was totally unable to access it.
I suspect the problem may tie in with the almost simultaneous update of Firefox (to 42.0) and an unexpected incompatibility between the new versions of each. I've mostly recovered by disabling the Passwords extension (avast still shows it as integrated with the browser, interestingly) and restoring a backup profile, which at least gives me most of my old passwords back into Firefox. Still can't get logged into Amazon or my ISP's customer service ("incorrect" username-password combo in both cases), although the latter will on request do the cleanup from their end.
Interesting situation with the toolbar icon. It it tested to work well with both Firefox 41 and 42 under normal circumstances. Could it have happened that the add-on got uninstalled or disabled during the update to 42?
Regarding the "good new passwords", it might be just a different expectation from some feature. It would be great if you could provide screenshots.
Sorry, no screenshots available ... I just checked FF add-ons, and both Passwords and SafePrice extensions are showing as installed but disabled, and considering I seem to have everything else working properly again, I'm gonna leave them that way for now.
It's a shame, I'm one of the unfortunates who has to re-use the same password everywhere (brain injury 20 years ago would make it impossible to remember good but different passwords), and a properly working password manager would have been the ideal solution. I take it that unless and until someone else can replicate my problem, I can't hope for a fix? I haven't as yet tried any of the 3rd-party managers, and was delighted -- temporarily, unfortunately -- to see it become available in avast, which I've happily used for maybe 15 years now.