The 1st Day Cover (which comes with franked stamps, and it's own day-of-issue postmark which was also designed by Mr McKean). inside is a card with (in this case) the very short stories, about Dragons, and Pixies, and Fairies, and mermaids and giants.
The presentation pack is unfranked, 'mint' stamps, and has the most amazing artwork, in addition to that on the stamps themselves. I keep returning to this, and each time I see something new. I am thinking of getting this framed to go on the wall, as it seems a waste to keep it tucked away in a box!
The presentation pack also includes the stories, and having bought both, I was surprised to find that the stories with the presentation pack are actually little longer - inside the 1st day cover they must have been edited so that they all fit onto a single, envelope-sized card. So I am glad I got both, as it means I have both the post-mark, and also the longer stories and the extra art! And I have, of course, also bought some stamps to actually, you know, stick on letters when I write to people. I was expecting the pictures and the words to be good, when I first heard about them, and they do not disappoint!