I studied Russian for several years at college, but started using Rosetta Stone since neglecting to maintain my skills. As other reviewers have mentioned, Rosetta Stone is somewhat like a glorified flashcard viewer and may be helpful with learning new vocabulary. Images and sentences appear on the screen and you are prompted to choose the correct words or case endings. Everything is multiple choice. Within the confines of that interface, the program can provide decent grammar and vocabulary drills, although it doesn't explain the grammar rules. The drills also tend to get very repetitive as the same sentences come up over and over again, which doesn't really challenge you to use the material you have learned. It's rote memorization, a method of learning that has significant drawbacks and limited benefit. Like running on a treadmill, it makes you think you are progressing a lot faster than you actually are. Also like a treadmill, you might find that all your work has taken you nowhere.
Case in point: I also bought Rosetta Stone Levels 1-5 for German to try to learn German as a total beginner, and having recently completed Level 1, I can say that very little of the material has actually stuck. I tried some of the interactive online games with another German student, and my mind totally blanked. After realizing that I actually didn't know any German, I decided to purchase some German language books online for some emergency remedial training.
For what it offers, I think Rosetta Stone is a bit overpriced as each language version I've used -- Russian, German, and Pashto -- is built upon the same cookie-cutter lesson plan, which completely ignores the grammatical and cultural aspects that are unique to every language. For example, case endings are fundamental to Russian grammar. Simply by changing a few letters at the end of a noun, you can significantly alter the meaning of a sentence. Whereas many native English speaking people can use English fluently without knowing the specifics of the grammar involved, you cannot speak Russian without having a solid grasp of the grammatical structure of the language. As there are no grammar lessons, explanations, or definitions in Rosetta Stone, it's up to you to go to other sources for a more structured lesson plan.
To make the best use of Rosetta Stone, I would advise to go at it with a lot of discipline and most importantly, to take notes while you are working through each lesson. As repetitive as Rosetta Stone is, the material will not stick by rote learning alone. Write the words and sentences down and study them. Analyze them and break them down using additional learning resources as necessary. Simply reading and typing the words, and picking from multiple choices on a computer screen is not sufficient. Also, if you don't get any speaking practice, it will be very hard to learn the language. You need to speak in order to hone your pronunciation, and you need to converse in order to gain true mastery of the language. The purpose of language is to communicate, so you can't expect to learn it if you don't actually use the language in a real-life situation. Furthermore, although the Russian pronunciations are accurate, there are many Russian sounds for which there are no equivalents in English, and there is just no substitute for having a native Russian speaker who can help you. There are many language exchange sites online for that purpose.
Learning a new language is a laudable endeavor, and I truly believe that it's in every person's best interests to learn a second (or third, or fourth) language. But learning a second language, as many who have tried already know, is very difficult. For that reason, I cannot fault Rosetta Stone for making promises (as in its advertisements) to bring the languages of the world to the masses. However, learning a language is not like teaching oneself to draw. It cannot be a solitary process. To make the most of Rosetta Stone (and to learn a language generally) you'll need additional textbooks, grammar books, and dictionaries; I also highly recommend an online language exchange site such as lang-8.com, coeffee.com, and others. Rosetta Stone's online community is a step in the right direction, but there is never anybody online, and I find the interactive component too rigid and confining.
I would not recommend Rosetta Stone as a standalone learning tool. It functions as a pretty good supplementary resource for the audio and visual aids it provides, but it is no substitute for a more structured language course in a classroom environment. That said, the reason that most of us are looking to buy a program like Rosetta Stone in the first place is because we don't have the time to enroll in a 4-days-a-week college language course. But if you put in the work and are resourceful and motivated, Rosetta Stone can be a useful study aid for self-learners.
Rosetta Stone recently bought out one of its major competitors, Livemocha, a community-driven online language learning site where you could practice speaking with native speakers and get constructive feedback on written and audio exercises. The advantage of the Livemocha interface vs. Rosetta Stone was that it was constantly added to and improved by its users and there was almost no limit to the quality and types of interactions you could create with other users. If Rosetta Stone's intended purpose was to truly foster language learning, why would they eliminate an invaluable resource for language learners that complemented and often surpassed Rosetta Stone? From the changes I've seen in the new Livemocha interface, it's obvious that their principle goal was to eliminate the competition by 1. eliminating the open community feel of the original Livemocha website and installing a severely restrictive tablet-style interface instead, essentially creating a Rosetta Stone Lite; and 2. making the new Livemocha website so user-unfriendly and tedious that there has been a mass exodus of members from the site, essentially killing it.
For all its faults, Livemocha was a better value than Rosetta Stone and offered users an interactive, expansive experience that Rosetta Stone will be unable to recreate because the key to the Livemocha experience was in the contributions of its users, which Rosetta Stone has effectively alienated. (You can read the unanimously negative member feedback on Livemocha's homepage.) From a business perspective I can understand why Rosetta Stone would try to kill its competition, but as a consumer I disapprove of this cutthroat tactic. They essentially destroyed an affordable resource that connected millions of language learners worldwide. For that reason I will not buy another Rosetta Stone product.