Take a gander:
Of course it looks stunning. And Meryl looks fierce post-transformation. The only real singing other than group stuff was Meryl singing "Stay with Me." She sounds lovely but (I can't believe I'm saying this) the last few notes "with me" sounded a bit...hard. Her voice is nicely light as the role requires, and I know I'm being really picky, but it's possibly my favorite note in the entire show. She doesn't use vibrato for that section and it comes across a bit amateur. It's my own fault for getting too attached to Bernadette Peters' version from the original production.
I know Meryl is an actress first and singer second, but I was just hoping for that last little section to be more of what I was used to. Regardless, she sounds brilliant otherwise, and based on the trailer it looks like the film could really deliver.