It works great on a single computer.
However, as others pointed out, firefox sync only syncs a snapshot of the last items that were fetched.
I use version 1.10 of the addon.
Edit: After update to 1.16 (or maybe before), sync began working for me.

as close to live bookmarks as i could find. i would recommend this for that main reason.

Excellent, thank you so much for this

Bonne extension, qui pallie à la fonctionnalité de lecture de flux RSS retirée de Firefox 64. Le seul problème est sa lenteur au moment de la mise à jour des flux, ce qui ralenti considérablement le système en entier (utilise la totalité de la RAM et du CPU sur une petite configuration). A corriger d'urgence, et ce sera parfait. Quelques bugs aussi lors de la souscription à un flux RSS (mauvaise URL prise en compte pour certains sites).

Good extension, which replace the RSS feed reading functionality removed from Firefox 64. The only problem is its slowness when updating feeds, which significantly slows down the whole system (uses all the RAM and CPU on a small configuration). This problem should be corrected urgently, and it will be perfect. Some bugs also when subscribing to an RSS feed (bad URL taken into account for some sites).

EDIT : les bugs de lenteur ont été corrigés, c'est parfait maintenant

C'est une bonne extension mais dommage qu'il n'y ait plus d'icône grise et orange pour distinguer les liens visités et ceux qui ne le sont pas. À mon avis, il faut la rajouter.

It's a good add-on but it lacks the gray and orange icons that made it easy to distinguish between visited and not visited links. It should be added.

Now that the performance problems have been fixed, I'm really happy with this extension and upping from 3 to 5 stars. The read indicators would be nice to have, but I'm not too fussed about them. So happy to have the Live Bookmarks functionality back - it really upset me that Mozilla deprecated and removed it. Thanks a bunch for creating this extension!

Downloaded this addon to reintegrate the live bookmarks feature that Firefox had removed in an update. Works just as well!

Since firefox no longer supports RSS feeds/live bookmarks, this Add-on is the perfect replacement. Thanks a lot!!!!

Mostly works as expected and is a suitable replacement for the FF live bookmarks. But synchronization between multiple FF instances still doesn't work (with v1.10) - it also didn't with 1.8 and as I've seen, the sync feature has been removed in the meantime (I think with 1.9). It should be possible to use FF sync for add-ons and their settings, right?

Im so glad I found this add-on when firefox removed the built in RSS feeds. Great!

Tried a few different RSS feed readers- Either too complicated, or not bright enough. This one is just right. Imported the .opml file, changed the default location to Bookmarks Toolbar, moved the icons to the previous location, renamed, and all is like it was before FF64 came and trashed what users use.. They keep nibbling at what we like to do... anyhow, that's another story. And not a nice one. This addon is definitely the go-to for minimal fuss. Yeah, could do with a colour change of what is read, and an ability to delete the list of feeds... maybe if enough of us say something???

This brings back my good old live bookmarks, thanks!

Nice alternative now that moz:lla have dropped RSS... ̶b̶u̶t̶ ̶d̶u̶d̶e̶,̶ ̶y̶a̶ ̶g̶o̶t̶t̶a̶ ̶a̶d̶d̶ ̶a̶ ̶'̶l̶i̶n̶k̶ ̶r̶e̶a̶d̶'̶ ̶i̶n̶d̶i̶c̶a̶t̶o̶r̶!̶
EDIT: v1.14 (20th Dec 2018)
Now with added... ✔Feed read indicator \o/

Is there a way to implement color change for read/unread news? Would help tremendously
Latest version has a check mark which solves the problem.