Rated 5 out of 5 stars
But something going wrong since 19-apr-2017. I used favourites, adblock rules, greasemonkey scripts and stylish css with my sync-account. But now all of these objects except stylish syncing properly. Even if i use clean FF profile, then only stylish-sync don't work anymore. I've been checked it with FF 52.0.2 and FF 53.0.