I listened to this podcast in the car with my 2 young children (6 and 3). It did everything I wanted it to - let them hear the Wizard of Oz story in its original form. Already they're asking for more podcasts - a problem because there's a distinct lack of (free) child-friendly podcast literature and audiobooks (hint, hint!).
The story was relatively well-read, although sometimes the reader seemed to get caught-up on enunciation, causing him to lose focus on the actual storytelling. Also there was a lot of differentiation between character voices which made the story easy for the kids to follow, but this meant some of the voices seemed a little strained (the female roles in particular). As an adult listening alone I think I would have opted to listen to a different podcast book instead, but my girls loved it, hence the 4 star review.
Overall I would recommend this podcast, and it is well suited to children over 5 years of age.