I've been using Eversync (Everhelper) Premium for a few years, and I couldn't be more pleased! I'd been using Xmarks forever, but when that app ceased to exist I had to look around for a suitable replacement and VOILA! I found this excellent Bookmark and Syncing App (with FVD Speed Dial) from Nimbus Web, and I hope they keep updating it forever. Highly recommended.

works reliably for me on firefox and chrome, and on macos, linux, and windows

Excellent stuff. Would be even more convenient if it came to Firefox for Android as well, but still great nonetheless! : )

افزونه‌ای بسیار کارآمد

Un gestore dei favoriti veramente utile che con firefox e MS Edge

I am able to sync my firefox and chrome bookmarks, and it's syncing speed is also fast. I recommend this extension (free one) to everyone who is using multiple browsers on multiple devices.