I've been using FullContact for over a year and I've been disappointed since then. Very clunky UI, lots of manual work to do. History on contacts that I don't care about and cannot get rid of. The inability to unmerge if you merge by mistake (often due to the slow web UI). After all these years, there's still no good solution that merges and cleans up your contacts! I'm really disappointed! How can we expect great things like AI and be afraid of AI destroying the humanity, when we can't even make contact management work right!