Good product but not on it's own
I recently got an online subscription to RS for Spanish(Latin America). At first, I thought it was great and used it alone. However, as the material got more advanced, I felt like I needed some sort of supplemental materials. I really needed to write things down to reinforce the words I had learned and how they all fit together. The online version has a course contents page that is basically a list of all the phrases used in the course organized by lesson. I printed that out and it was extremely helpful. I made my own list in a notebook of verbs, nouns etc so that I could study when away from my computer.
Everyone learns differently and I'm sure there are people who can learn and remember this stuff just from going through the program but I am not one of them.
I will say that RS customer service is horrid and I would be upset if I had to deal with them on a regular basis. They were totally dismissive when I asked if they offered any workbooks or other materials to help. They gave me some stupid answer about how I shouldn't need that stuff and how Rosetta Stone will make you fluent without translations and books. That is total bs, don't believe it.
Don't get me wrong, RS is a great tool. I knew nothing about Spanish before I got the program and have learned a ton and I'm not even finished with the first level. I know that I will learn much more by the time I am done and will not have felt like my money was wasted.
However, I am confident that I will not be fluent in Spanish after I have finished the program. RS is such a great program for what it is, which is a beginner to intermediate program. And even for that, you will probably need some other materials to help you learn. I guess the reason RS lies about what the program can do is that people won't pay so much money for a program that won't take you all the way. I would recommend it keeping in mind that you will probably need to invest in further materials.