I've never seen her onstage, so maybe that makes my opinion completely invalid to some people. If it does, just stop reading. I don't want to deal with you.
I like her in some roles and I hate her in others. I hate the tempo she takes "Worst Pies in London" at off the top of my head. I just don't like her as Mrs. Lovett, both in the concert version and in the clips I've seen of the revival. It's just not the role for her, in my opinion.
However, her Mama Rose is stunning.
Some people paint, some people sew, I meddle.