I have two of the Adventures with Nicholas books. I have this one, and the Missing Cat. I'm an adult learner and I find them really useful. There's really no better way to learn pronunciation and sentence structure than to listen and read along at the same time. I'm really glad they offer the texts on here as well. I bought the Missing Cat set, so I have the book, but having a cassette tape is a pain. I was happy to find them for download, but skeptical without the book. The texts they offer are fine for me though. I can imagine the pictures would make it more fun for a child.
The simplicity of the stories is wonderful. After reading the English translation two or three times, I can usually understand the whole story without it, and just listen to the audio while walking the dog. The only real complaint I have is the second half of the audio. They go over a list of vocabulary, but they don't include the gender articles with the nouns. This is a huge drawback because in German, it is really so essential to know the gender of every noun. The songs are also a little creepy. Not even sure a kid would like them.
I only wish Berlitz would make more programs like this, but geared towards adults. I enjoy the learning concept, but feel a little ridiculous reading a story about buying Grandma a present. Also when the narrator introduces Nicholas at the beginning she says, "he is just about your age!" I think, really? He is 25? All of that aside though, it is fun and is an excellent learning tool for people of all ages.