I'm not inclined to run
anything that's remotely related to password security in a browser extension (I do use the Firefox built-in password manager to simplify logging in to sites like this one, where I have no money at stake and nothing much to lose but my pride).
For high-value logins, I use Passwordsafe. It's annoying; the scroll behaviour is annoying, and it's Windows-only, which is sad. But it's resolutely local and un-networked, and I'm confident that my secrets are well-protected by my (complex, long, memorized) master password.