Good work Rated 5 out of 5 stars
As Update notifier broke since FF4.0 it was a matter of time til some will pick the towel.
It works fine, it looks nice, and it makes it easier to stay updated.
I'm missing the tooltip saying which updates are available and the option to install the update from the addon bar, I hope it will come soon.
Keep the good work.
Version 1.4 adds a tooltip that shows name and new version available. I most likely won't be adding a full menu with options to install/restart.