Both Rocket French and Rosetta Stone offer full-range software programs. Both programs have games to make the programs more enjoyable and both offer tests so that you can determine what you have learned and focus on any weak spots.
Rocket French stresses natural language learning. Natural language learning focuses on learning a new language in the same manner that you learned your native language. There is less emphasis on grammar and more importance is placed on vocabulary and the repetition of key phrases.
Rosetta Stone emphasizes the traditional language learning mode of repetition along with sentence structure. Less importance is placed on vocabulary than on grammar. The language learning with Rosetta Stone is more formal than with Rocket French.
You will work through each program at your own pace. If you dedicate an hour a day, you would finish Rocket French in about a month. Rosetta Stone would require about two months to complete.
Rocket French does offer a free six-day program that will give you a foundation of French in that time frame.
Both of these programs offer similar benefits. They both offer proven ways to learn French, not just by language teachers, but also by those who have tried one or both programs.
Both programs offer the ability to learn French at your own pace and to review the programs whenever you want.
They both incorporate audio and video components into their programs. Each offers a total learning experience that is similar in many ways to a private tutor or learning in a classroom setting.
Because of the differences between these two programs, it's important to consider what your reasons are for learning French.
If you are learning for your own pleasure, travel and the ability to speak in a different language, then Rocket French offers more of what you seek.
If you are learning French for business, translation or academic reasons, then Rosetta Stone and the emphasis it places on grammar might be your best choice.
In the end, however, you need to choose the program that best fits your individual learning style.
The cost between these two programs is vastly different. As of October 2009, Rocket French is available for $99. The Rosetta Stone French program, parts I and II, is available for $409. The Rocket French program in its entirety is the equivalent of Rosetta Stone French I and II.
With Rocket French, you also receive a lifetime membership to the Rocket French forums, and any software upgrades are free. There are no Rosetta Stone forums or included upgrades.