I have the megapack. You learn the basics VERY fast with it. Been trying to learn Italian. Right now, I've gone through the listening and reading segments and find I can understand Italian really well, but interestingly enough I can't speak it worth a damn.
They have sections for writing and speaking though (you need a microphone) as well. Once I feel really confident in level 1 with listening and reading, I'll do the writing and speaking exercises.
When I'm done with Italian, I plan on learning Mandarin Chinese.
Hopefully when I manage to finish Mandarin, they'll have a level 2 Hindi out.
It's an understatement to say it works. You just have to make sure to devote time and effort into it. But honestly I felt like I learned more in 1 week of using Rosetta Stone than I did in 2 semesters of college, nevermind 4 years of highschool.
Btw, in case you're wondering about my odd language choices, I want to learn Italian because the old lady and I have vacationed there a number of times and we love it but can't understand a word anyone is saying; it'd be nice to actually be able to converse with folks.
Mandarin because I have a number of employees who are Chinese and I may open up a remote branch in China. Plus, when the owner of the company bothers to take the time to learn your language you feel more welcome and at home. I like my employees to feel as much like the company is their extended family.
As for Hindi, same reason as above. I have a lot of Indian employees and I'm considering opening up a remote branch of the company in India.