With its prohibitive tone distinctions, large number of vocals and alien consonants, Vietnamese is one of the most difficult languages to learn in the world. Unfortunately, this course does a very poor job with conveying how the language is to be spoken, and similar to many other DIY language courses, the exercises at the end of each lesson are thrown in haphazardly and have little relation to the lesson they accompany.
The course begins with an introduction to the tones. They are not given names (low falling, glottal stop, mid rising, et.c.) on the cd or any explanation of their differences. In fact, at first listen they sound pretty much the same and only after rewinding the tape or skipping back on the cd hundreds of times will you eventually nail them. Next comes a list of the vietnamese vocals, consonants and diphtongs. On the CD, they are spoken in sequence (fast!) by a number of native speakers of different age and sex. This is actually a good way of getting the gist of the relative pitch of the tones, but for the actual pronounciation, just saying a bunch of morphs in sequence does little for someone without a trained ear. No examples are given of similar sounds in languages more commonly known to the average user of the course (like English, German or French).
Once (or rather, if) you have gotten past the gruelling 10-minute introduction track, you go on to the dialogues themselves. The speakers all speak in a normal conversational tempo, which in vietnamese terms means faster than you can possibly pick up the distinctions. Only by deliberate analysis of individual words using a computer and headphones will you come anywhere near learning the language. Subsequent dialogues only get worse, and sometimes use words and phrases not in the vocabulary provided for each lesson or the dictionary at the back of the book. There is a lot of background noise on the recordings, using headphones you can hear typing, muffled voices, computer fans, et.c. At the end of each dialogue, you'll be asked to answer some questions ("how did the speaker introduce Ms. Phuong?"), but the time given you to answer the questions is next to none and it is downright impossible for someone just learning the language to mimic the native speakers using the recordings provided.
The exercises at the back of each lesson seem to have been tacked on without much effort. They use little of the vocabulary of each lesson and give little insight into the grammar. The solutions for the exercises at the back of the book are poorly organized and hard to read, and sometimes don't match the exercises at all.
All in all, this was a poor purchase and I felt I gained little for the hard work I put into it. As a student of mandarin and someone fairly good at mimicking speech patterns, accents and languages, I still found it next to impossible to understand and learn Vietnamese from this course. My verdict: do not buy.