Yeah, Rosetta Stone is fun to start with. It doesn't feel like work, well, not much.
I would prefer that at some point they would actually try to teach grammar and so forth, in French like they would to French children. Instead they just tell you how to say stuff and try to get you to figure out what they are talking about. It's a nice idea about learning like a native would, but 1) we are not babies and don't need to start from nothing 2) unlike babies, we don't have 24 hours a day to devote to learning a new language and how to walk, etc. 3) just purely paying attention to what others are saying is not how people learn. Learning also comes from interacting. That's why it is a good supplement to classroom learning (or interaction with French people at least), but not a replacement for it.
If you can devote the time, however, I would recommend going beyond classroom learning and if you are new to the language, something like RS is a good idea. Hey, I could sell you my RS for $100.
I could still use it, but ...