This is real Sondheim, not disneyfied Sondheim.
The harmonies are 'bad', the characters insane, the acting crass and the music indiscrete. But this is what makes Sondheim, Sondheim!
If you want to see Sweeney Todd, as Sweeney Todd, then go for it, and get this!
My only reservation is of the choice of some actors, not Sweeney or Lovett, but of Toby, and to a lesser extent, Johanna. Perhaps, though, this is merely them, unable to stand up and be seen alongside greats such as Lansbury & Hearn.
Staging is brilliant, music is fantastic. If you want to see what Sweeney is all about, then try this for size!