Let me guess, you want to learn Chinese so you can watch old Kung Fu movies without the English dubs or the captions, right?

I tried it, but it was about 5-6 years ago, so who knows what has changed since then, but I’ll tell you my experience.
I took it for Spanish, and I really knew nothing going in, except for the stuff that has seeped its way into American culture (asta la vista, me casa es su casa, uno, dos, tres, etc.).
I thought the method they used was pretty effective. My only real gripe was with the voice recognition software. Sometimes you feel you say a word right, but they say you’re wrong, then you repeat the same thing you just said, but this time they say it’s correct, then sometimes you’d say the word 5+ times the exact same way before they finally accept it on the 6th try. Sure maybe it was me mumbling or not speaking clearly or not using the proper accents, but sometimes you’d get stuck on a word/phrase you’ve said correctly (according to them) like 10 times before. This didn’t happen a lot, but the once in a while that it did happen could really be frustrating.
Once you move on from simple words to phrases, a couple of times I do remember having to go break the phrase down in google translate to figure out what exactly I was saying, or what part of the phrase actually meant.
It also helps if you actually know somebody that speaks the language you're learning so you can practice with them. I'd make it a point to try to go talk to a couple of my Spanish speaking friends at work everyday and try to use what I learned with them. And they helped explain things or give me tips or hints. That was a really helpful supplement to the Rosetta Stone stuff, and I think it would have been a lot tougher without it.
Of course, like any complex thing you want to learn, it takes a lot of work, and you have to stay consistent with it. What I tried to do was use the software for about a half hour a day. When I did that consistently, I felt I moved along pretty well. But when I missed a few days or a week, I felt a little lost once I picked it up again. I never really progressed that far, I got about 4-6 weeks into Spanish on 2 different occasions, then ended up not being able to stick with it for whatever reason. So the more advanced stuff, I really have no idea how it goes, but the early stuff I thought was good.
You can set up multiple accounts for the whole family on one computer too, so you can all do your own thing at your own pace, but they only let you install it on 2 computers. So if you, your wife, your kid(s) all have your own computer and wanted to install it on everyone’s personal computer you wouldn’t be able to, but if you have a family computer everyone shares, then no problem. .
When I used it, I liked it, and would recommend it, as long as you can stick with it. It ended up being a pretty expensive headset (as that’s the only thing I still use) for me, but I plan on picking it up again someday, so there’s still hope!