The writing is fun and whimsical, to say the least. I had to wrap my mind around stories that were completely unreal and that stretched the imagination of a child, (which is different than the imagination of an adult). I feel like adult fiction is things that haven't happened, but could, and might. But Mary Poppins is a painting-stars-in-the-sky, visiting-the-zoo-with-humans-in-the-cages, Christmas-shopping-with-a-constellation kind of fantasy. You really have to read it as a child.
Now one thing should be made clear, Mary Poppins the book is not the plot of Mary Poppins the movie – unless I just haven't watched carefully enough. The Disney movie only really takes the character and gives her new experiences. I did appreciate that it made me wonder what was coming next rather than just think about the movie (and then complain about how they misinterpreted the book). Also, in my opinion, there is no real plot to this book. I assume Travers intended it to be that way. Each chapter is a short story that has its own conflict and resolution. As a whole, there is not much of a storyline at all.
Overall, if you can tap into your (former) imagination for a week or so, I'd say that Mary Poppins is a fun read. I'll admit – it was tough at times. But even a 'spoonful of sugar' won't help this one down if it's not the kind of thing you are into."
Other Topics of Interest:
Reflections: The Wonderful Wizard of Oz
Reflections: Alice's Adventures in Wonderland