I've been working for some time on a post comparing four different editions of the 1923 Newbery winner, The Voyages of Doctor Dolittle by Hugh Lofting. The post got so long that I set it up on its own website. Let me know what you think in the comments there or here.
Bottom line: There are some editions out there that do not make it clear that they have been revised from the 1922 original. Even with those that are upfront about changes, it's good to know exactly what is different. Buyer beware!