I've finished Unit 1 in Rosetta Stone Farsi. There are currently 2 units available.
Pros to Rosetta Stone:
It's easy to sit down and spend a few minutes every day studying your language
You get lots of listening practice
It's simple to use, even for children
It's limited in what you can practice, and there's not much opportunity to create
EXPENSIVE- I think it's unreasonably expensive
The first 8 lessons covered pretty much what my Persian books covers- present tense, comparatives, adjectives, etc, and a lot of the same vocabulary. I do think RS is useful when it's used with other resources, but when you have to spend this much, I don't know if I can recommend it, especially if only one person will be using it.
As for Persian books, we have An Introduction to Persian and Teach Yourself Modern Persian. I like the first, my husband likes the second. And I think he would really dislike the first and I definitely dislike the second. Thackston is pretty technical with its grammatical terms, but TYMP isn't at all useful for grammar, and it's nice sometimes to be able to just see the conjugations. There really isn't a generally useful book for Persian.
For other posts about RS, click on the Rosetta Stone link below.