I have been using RS for Spanish also, however I'd have to agree that it is very, very basic up to level two, and that for the extensive price tag it may not be quite right for anyone who is currently or has had any significant training in Spanish already.
I'll qualify this by saying that it is fantastic when used in conjunction with some basic language curricula to get basics about grammar down and to get some additional vocabulary going. I'm also using the Vistas language material, and I practice vocabulary on my own. In doing this I am trying to learn Spanish the same was I started learning English when I was 8 years old - I had immersion (through going to school in the States with all English-speakers), and I trained also with written material and studied vocabulary extensively. RS provides the immersion, primary-language learning style, while I am able to learn a greater volume of words through more standard study with Vista and my trusty 501.
We will see how it goes
, but I can say that nothing replaces immersion...
luego,
Jackson