It was interesting and amusing, but I doubt it will take off. The essential question about this play is why? Sweeny Todd has already dealt with the basic theme, with better music.
Why a costume drama? The period is not really relevant to the theme so just makes the whole thing look dated, instead of like a new musical.
We went to the pre show lecture on the history of musical theatre in America. The lecturer finished by wondering if this musical would be the next break through and we would all be able to claim to have been in at the beginning, or whether it would die a quick death and we could all be among the very small group who ever see it. My money is on the latter!