Good but poorly supported Rated 3 out of 5 stars
This is quite a good extension BUT the developers are apparently very slow to update it for new versions of Firefox which is really very annoying.
The fork of the project Sage-Too is apparently no better as one developer has abandoned the project citing selfish Firefox users. Is it selfish to want what should be standard in the browser? By default Firefox is quite ancient in it's feed reading abilities, no matter how much their marketing team wants to pimp "Live Bookmarks", and therefore a decent extension is needed and must be maintained.
Users get excited about new versions of Firefox and that excitement is met with a thundering brick wall when extensions don't update in time. It's not as if Mozilla doesn't give extension developers plenty of notice.