I liked the book better than the movie, but I liked the audiobook more than either. It really added something to hear David Tennant's take on Toothless's voice and to hear the examples of Dragonese. 
 I find it annoying that the book contains only two female characters (one a dragon and one a mom whose bra has a larger role in the story than she does), but I find that rather less annoying than the fact that the movie only has two female characters and one is there almost exclusively as a love interest for the main character. But I'm reviewing the book here, so I'll stop complaining about the movie. 
 The book was a cute take on a coming-of-age story. The style was a little more graphic-novely than I usually like, the language was rather simple, and I found the shifting fonts somewhat distracting, but it was a fun, fast read for both me and my 7.5yo daughter. I enjoyed the vivid visuals (the word-inspired visuals, not the illustrations so much) and found that the idea of each boy getting a dragon to train as a rite of passage really tweaked my imagination. I also loved that nobody except Hiccup could understand what the dragons were saying. 
 So, fun story, but I don't think we'll be rushing out to get the other books in the series.