I have Rosetta Stone for German (1, 2, and 3.) While I have an advantage of having lived in Germany for five years, I still believe this is some incredible software. There are times when it simply becomes frustrating, though. For instance, when you have to write what you hear the speaker say. While it may sound like an, "h" it could be a, "j." The writing is by far the most frustrating part of the program.
I feel you have an advantage with Rosetta Stone. It's interactive and amusing, plus you have people from the actual country of your language choice that are being used to make the recordings. So you hear the language in its actual accent and pronunciation. The only down-side to the program: Not enough writing, no tests, no due dates. While that may be an advantage to some, it can help others slack a little and slow down on their progress of learning their language of choice.
I'd say go with it! I certainly love it.