First off, I pulled this off my parents' bookshelf, and it was a joy to read a hardcover from 1914, with illustrations. It looks just like this edition I've selected, but it's pale blue instead of red.

Secondly, I was shocked at how different the novel is from the movie. I'm going to rewatch it soon.
***UPDATED TO ADD: Mom and I watched the movie again. It is so. Very. Different. I think its greatest weakness is in character development. Pollyanna is kinda snotty sometimes and Aunt Polly is almost wholly unsympathetic. No changes are visible and yet somehow she's declaring that she loves Pollyanna like her own daughter. Everything moved too fast - the book does much better job of showing how Pollyanna wins over the various people in town, and especially Aunt Polly. The "mystery" of Aunt Polly's suitor is also much more enjoyable and somehow the whole story just held together better without spending so much time on town politics. I don't DISlike the movie, but it doesn't hold a candle to the sensitivity and warmth of the book.