Notice how Rachel has only 1 post praising Knewton.
I would only advise you not to throw away your money without finding out from other students.
I joined Knewton, in Sep 2010, and always scored above 70% in all the English home work assignments and above 80% in Maths homework. But surprisingly those results did not translate into the exam. Mathematics did but that was mostly my hard work and prior knowledge.
The teachers are Amazing in Teaching. But the Knewton home work and practice questions SUCK, their concept of practice is copying all the official type questions and find & replace nouns, how ridiculous is that. They looted 600$ for this non sense. I mean, even the practice exam questions have same official style questions with just nouns changed.
Before any fanboys start defending, I did not ask them my money back because it will be cheap on my behalf, to use their system and say that I wont pay anything.
They need to overhaul their practice questions. How lazy can one be in just copying questions from other places.
I am disappointed with their home work and practice questions. Their Teachers and support staff are very good, both personally and subject wise.