I bought the OG Guide 12th edition, did the GMAT Pill (which was a waste of time and they only give you a month to refund which is impossible to rate in a month), studied online forums, read and went through all of the Manhattan guides and I still got a low score. I decided to try the Knewton course because of the 50 point money back guarantee. I wasn't sure if it would actually work, but I did all of the homework and completed all of the quizzes. The 6 free tests were especially helpful and the concept queue was helpful in letting me know what I needed to work on. There were resources for more tests that I had access to, but I didn't do. My score probably would have increased had I concentrated more on taking more tests and reviewing concepts. Those tests are invaluable as well as the detailed explanation on the webinars and extra practice homework. I wish I would have done Knewton in the beginning and it would have saved me a lot of money and wasted time. Spend the money!!

I was totally disappointed with the Knewton "On Demand" Course for the following reasons

1) They don't have any fixed time frame to respond to your verbal/quant queries, as a result of this there are questions that go unanswered. I found it easier and quicker to get a response to my queries on the forums.

2) The instructors who respond to your queries seem to have an attitude. i.e they don't entertain the 'What if' scenarios. For example, I had a query regarding one of the Sentence Correction questions; I wanted to know whether writing the sentence in another way would be ok; these guys don't entertain such kind of queries, because according to them there are many ways to write a sentence. On the one hand, they may be correct, on the other hand, they don't understand that they could actually be helping the customer answer his/her specific query.

3) They claim to have 3800+ questions. This is bullshit. I wrote them an email and I received a reply saying that the questions span the 13 sessions including the 6 CAT's. I decided to actually count the questions. To my surprise, I counted 1606 questions. If you include the 6 CAT's, it comes to 2074. They have a pre-assignment test that you take before watching the videos, for some of the sections such as, Quant, SC, you will see non-gmat format questions, I counted these questions as well to give them the benefit of doubt, nevertheless, the number I got is no where close to their supposed number of questions.

4) I really doubt the adaptive nature of the course that I took. I couldn't tell how I was being challenged by the adaptive nature of their questions.

5) I came across their program on this website, so I directly went to their site to apply for the course; it was only later that I realized that had I clicked on the link advertised on this site, I could have gotten another $50 discount. I wrote them an email about this, but I was refused the additional discount. In my opinion they were being a bit cheap about this.

6) The CATs cannot be reset by the customer. Also, if you don't complete the test within the time limit, the questions you miss are not displayed when you review the test.

Feeling inadequate, I had to spend money on other test prep company products. I was wondering whether I could sue them for lying about point #3, unfortunately, I don't live in the USA.

Needless to say, I was terribly disappointed and the entire experience was unpleasant. I would NOT recommend Knewton to anyone. Please thoroughly research every company's product before investing your money, is my advise

P.S. I would have written this review even if I "cracked" the GMAT

OK everybody listen up: This is an awesome GMAT course. I have never taken online classes before. However, I have taken classes at college with boring teachers. This class has the coolest dudes as teachers, you get so much material to print off and review it in case you don't have access to the internet. You have a question? They answer is super quickly. I am going to take the GMAT in January and I am very excited what the score is going to look like. If I suck, my fault. Knewton really doesn't leave any questions open. And, just for your information: I was a total fail in maths, didn't even dare to take a mock test to start off with to find out my level. I gained confidence and knowledge. Knewton, you rock!

The online instant classes are great. You can go at your own pace and at the same time try to follow the schedule they have. I never took a live class because I thought it was sometimes either too fast or too slow. The "On Demand" allowed me to pause the video and do whatever I want.

Problems are explained in a very detailed way.

Instructors are great. They even try to make the class funny even though its a prerecorded video. 3 out of the 4 teachers are great. the only negative comment goes to Jen Rugani. She speaks way too fast and without taking some time to actually breathe. Then she stops and makes a weird noise just to catch her breath. Its very distracting and hard to follow when she is speaking. Everyone else is great.