Firstly I must strongly refute the negative comment by the above critic - NT I think.
Anyway, I have just turned 60 but left this movie with a huge childlike grin on my face, saying to my wife, "Now I just can't wait to see it again!".
I thought all the actors did a fine job - especially Li-Manuel Miranda, who played Jack. He was utterly delightful, a real revelation. As for Emily Blunt as Mary Poppins, she was indeed "practically perfect in every way!". In addition it was lovely to see Dick Van Dyke doing his thing again, and the uber talented Ben Wishaw played his Michael perfectly.
DO NOT MISS THIS LOVELY MOVIE! 12/10!