I like the Pimsleur materials because they focus on conversation. The audio materials leave time for you to repeat the phrases after listening. It's handy if you have a long commute to work. For Japanese, using Pimsleur is a good starting point because it temporarily removes the distraction of learning Kanji, Hiragana and Katakana. While these are all good to learn, most of the people I know who have become fluent in Japanese speaking, listening, reading and writing have focused on becoming conversational first. One drawback to Pimsleur is cost. If you are thinking you want to invest in the audio materials, check to see if your local library has Pimsleur materials you can borrow to determine whether Pimsleur works well for you before you buy.