I am using Firefox Sync because I use Firefox as my primary browser, but Firefox Sync completely messes up my bookmarks, creating duplicates each time I log on to one of my computer. Seems to work only for a single-computer setup, which is quite outdated nowadays.
Xmarks has been discontinued since months. Last time I tried it because the website came back online I don't know why, the server wasn't responding at all.
Manually importing bookmarks works, AGAIN, for a single-computer setup. But I will never always think about saving my bookmarks when I leave one computer, copy that somewhere (e.g., Dropbox), and restoring when logging on another computer.
It seems that the only way is now to bypass the browser's bookmarks and setup a web server with an HTML page with links, and update the page manually to add bookmarks, or get rid of all computers except one in order to use some bookmark-syncing options above.
4@Antony can confirm. Do not leave bookmark sync turned on in Chrome Sync. Bad things will happen – cavalcade – 2014-10-21T05:56:58.967
not yet compatible with firefox quantum – user26631 – 2017-11-24T09:35:38.767
5Xmarks is now planned to be discontinued, so EverSync may be the best alternative currently. – JimNim – 2018-03-30T16:13:55.637
20As a common sense, make sure to turn off bookmarks sync in both Chrome & Firefox on all machines prior to using Xmarks. It is truly a nightmare when all three bookmarks sync service are fighting, duplicating exponentially bookmarks across 14+ browsers among 6 or 7 boxes. – Antony – 2012-05-22T16:06:33.740