FWIW, I thought Dick Van Dyke's spot was the highlight. Mostly I liked the movie, but mainly because of the actors playing the entire Banks family, who were lovely. Emily Blunt's version of Mary didn't really work for me. She came across as someone that nobody would really want to spend much time with if she didn't do magic from time to time.
I was kind of puzzled by Angela Lansbury's bit. She's another of those great performers it's always good to see (I've been lucky enough to see her on stage twice, in "Sweeney Todd" and "Blythe Spirit"), but her scene was clearly written for the purpose of offering a cameo to Julie Andrews. Andrews declined, it's been reported, because she didn't want to crowd in on Emily Blunt's moment, a fine sentiment. But without her there was no reason for 3/4 of what Lansbury did, besides handing out the balloons and saying, "Be sure to take the right one."
I went into the moving wanting to love it and fearing I'd hate it, but came out sorta in between. But they really did need Paul to write the songs, IMHO.
Here's an interesting take on the film's ending [SPOILER ALERT!!!]