I've read this book twice now (the first time was six years prior to the second). I had the illustrated version for the second reading and I would definitely recommend that version.

The tongue-in-cheek fantasy is quite fun (remembering that the entire thing is fiction).

It is not told in the same fashion as the movie. The novel is an "abridgment" of the original, and while the concept of the story being read to a sick child is mention, it is not the main storytelling method. That child is now and author remembering that first telling and then abridging the original so that others may have a similar experience and not be distracted by the hundreds of pages of boring "history" and commentary.