The extension's actually ok, but the service is not. Would leave zero stars if it were an option.

- the much-touted UI is...basically the same as Firefox's ancient one with a few ajax flourishes
- what's worse, the UI is *very* unreliable: you move something and find out a few minutes later it didn't move at all even though the UI *showed* it in the new location; this happened dozens of times
- you can't export the collections: it would only let me export the bookmark URLs (not grouped/tagged) or the *original* data I uploaded
- the "AI" took an > 1 hour to do its "magic": with ~400 bookmarks, made a few reasonable suggestions, then *never worked again* (even after I substantially reorganized things, it'd tell me "not enough data...")

TL;DR: the extension's a pretty good front end for a service that's not worth using and won't let you export your own data.