Rated 5 out of 5 stars
NB: if you use Firefox sync, you'll still need to enter Firefox's master password, even if your Mac Keychain is unlocked. "Firefox Sync is not yet properly supported - these passwords will still be written to your Firefox password storage." (Developer comments on this page, v 1.1.3.)This review is for a previous version of the add-on (1.1.3).