As Xmarks is ending on 1st May 2018, I decided to give Eversync a try.

Well, I'm not disappointed at all : works perfectly with 3 browsers (Cyberfox, Waterfox and SRWare Iron), on several computers (on Win10 1709 and now on Win10 1803-Build 17133.1).

So, a BIG thank to the developers and let's hope that it continues to work like that ! :-)