I don't like the premise of the original Curious George story, but I do like the stories that have come out of that premise. Before I started reading the book, I was afraid that George would end up in the monkey cage. He doesn't, and he even helps out a little boy who lost his balloon to the monkeys. My five-year-old son has no problem with Curious George. He sees George as a five-year-old boy who is really good at climbing. And that is why the stories work.
The illustrations, even in the first Curious George book, are absolute perfection. I wouldn't change one line of them, although, I am glad that the zoos that we visit bear no resemblance to the zoo in this book.