Hi,
I used the Rosetta Stone online for learning Brazilian Portuguese.
I found this 'immersion' approach excellent for learning vocabulary (and I mean really learning, not just reading it once and forgetting it ).
However, it wasn't really useful at all for grammar. Now of course, Portuguese, being a Romance language, is alot closer to English in grammar, pronunciation and vocab. and therefore not nearly so difficult as Russian.
I would tend to think the Russian version would be a bit useless... but of course it is 'muito barato' (very cheap in Portuguese ).

I have a Russian CD-ROM from Linguaphone which seems to take a similar 'trendy' immersion approach. Right now I can't use it at all (only been learning a couple of weeks) and am sticking with a boring old fashioned Penguin Russian text which is actually teaching me all the tiresome rules.