Missing: The Other Side is yet another in a very long list of South Korean series.
Is it any good? Yes, its watchable with a reasonable, if not entirely original, back story, of a ghost village, only certain living people can interact with.
Acting is decent but then I'm yet to encounter a Korean series, where that wasn't the case. Main characters are likeable and believable, with solid chemistry.
Perhaps my only criticism, is too many sub plots, that often feel like padding and make this series feel overly long. I did find myself watching an episode or two and then coming back to this series, a week or more later.
In summary, watchable, well acted but perhaps a little overly long.