Hands-Down best bookmark cross-browser sync.
The ability to change sync frequency/authentication/locations is perfect!
If you use Nextcloud, it gets even better!

Great Add-on. Connected it to my Nextcloud and had an instant backup of my bookmarks/Sync to other devices. Gives you great options in terms of how/where to save the bookmarks, sync by merging Server and Client or make one override the other. Has all the options you need to make a a customized setup. Thanks!

Install was super simple. Add to Browser, Fill in Server and Login, Create a Sync task and you are set.

Had no issuses, works as intended from the first second.

完美契合我的需求，作者太棒了

Love It - works like a charm.

It worked very well and the feature that you can sync Bookmark folders is pretty nice. However, since the upgrade to the newest Nextcloud/Bookmark version it has an error:
Nextcloud log: Call to undefined function gmp_init()
Edit: Now it works again, thanks for the help :)

This add-on made a mess of my bookmarks. It did not respect my bookmark folders or order, and ignored the folder I told it to make on the server side.

Nice try, would have loved to use it, but it is useless as it is now.

Webdavs work, but nextcloud keeps saying "E019: HTTP status 500. Failed GET request. Check your server configuration and log." It is my own nextcloud install- with bookmarks 1.0.6

Probably the only addon that supports sync on selected folders (not all bookmarks).
One feature i miss is support to force pull/push sync, sometimes i don't want to merge.

Funktionierte bei ersten Tests recht gut. Danke! Leider werden keine Tags synchronisiert. Die benötigt man für die Andriod App, da diese nun wieder keine Ordner kann. Ich werde sicher in 1...2 Jahren nochmal vorbei schauen. Danke!

Nginx + webdav module + floccus = ❤

It work's great, but it will be better (why it's only 4 star) if this app use oauth or the second factor (like u2f or otp), for the connexion, because i don't like the application password

First: works as it should without any restriction, very very good extension both for Firefox and my Nextcloud. Fifth star not assigned in fact that there's no Firefox add-on for Android version and so it is not usable for me for I don't have other devices to sync than my Android ones.
A minor proposal: A list view of the bookmarks like in Firefox itself would increase usability. The graphics for each bookmark are a bit large and if you have hundreds like me or maybe a thousand of them you're forced to scroll a lot or to use the search bar extensively.

Appendix: The list view is a comfortable advantage, thanks a lot.

Works as advertised, great dev support.

When Xmarks disappeared I was stuck for a while. But then I installed a NextCloudPi server at home which was pretty easy and has a load of benefits beside, and found floccus. It was was not working when I first tried it, but Marcel has been chipping away at it beautifully and as of version 3 it's well and truly slick and a satisfactory Xmarks replacement!