Like others, I have followed the link to the Horn Book's history archives to check out Elinor Cameron's scorn for Charlie and the Chocolate Factory, and Dahl's rebuttal (Here). To Cameron's mind, Charlie was as horrible as television--disastrous junk food for growing young minds (she also had serious, and totally warranted, objections to the enslavement of the Oompa Loompas-- wandering off track, anyone else deeply troubled by the enslavement of the sentient engines on the Island of Sodor?). I went on to read the letters to the editor, and found one by Ursula Le Guin (here). She didn't care for the book either, certainly not enough to spend her time reading it out loud to her children, but she recognized its escapist appeal for the young. This, in turn, reminded me of an article written by Le Guin in the New Statesman last December (here), in which Le Guin writes about lifelong reading of fantasy, how many grown-ups return to books loved as a child because of "their [the books'] strict standard of emotional honesty."
36 years have gone by since Cameron attacked Charlie. Many of us who read the book in the 1970s have grown up to become life long re-readers of children's books, and many of us have become the ones who read out loud to children. I remember reading Charlie when I was 8 or so, and can vividly recall my almost horrified fascination with it (it was grotesque, overdone, with so many incredible, marvellous details...all those fantastic details). But even at the time, I didn't think it has much of the numinous in it -- that transcendent moment when a book socks you in the heart-- nor does it have much emotional honesty (which I think I'd know if I saw it, but can't quite define). I haven't re-read it in decades, and there are certainly many other books higher on the list of things to read to my boys.
The parallels between Charlie and Harry Potter are obvious, especially the "it encourage reluctant readers to read" bit. I'm not in any hurry to read Harry to my boys either. Some books, I think, are just meant to be escapist indulgences. And if their main merit is encouraging reading, let the kids read it themselves. In the same vein, I will not read Captain Underpants out loud.
However, I'd be perfectly happy to have either Charlie or Harry as audio books on long car trips of the future, when escaping takes on more importance with every mile.