I enjoyed it, unlike (most of!) you lot! 
Are we sure Mark was dead at the end? the moment he looked up from the newspaper and started to walk towards the bathroom scene again, I assumed he was just in another dream and that the witches had cursed him, knowing he was a wrong'un, to have the dream over and over - he had asked them to make the dreams stop but they were (after all) "good witches" and on the side of his wives.
I didn't spot Osbourne as the killer - yet the 'the only ones left alive on that list are...' conversation was a clear clue - a sign of a satisfying mystery in my book.
Loved the witches, by the way! the Maiden, the Mother, and the Crone, as per tradition? - thought they were perfect in the roles.