Hi mousymouse,
While it's true that a lot of test prep companies have some sort of online offering, Knewton uses a unique adaptive learning engine that I assure you is beyond what is offered at the traditional companies. A traditional course offered over the web and a truly adaptive platform are two dramatically different things, often muddled in marketing speak. The technology that Knewton has built actually extends way beyond test prep -- it can power content across the educational spectrum. We break content down to the atomic level (singular concepts) so that we can assess your exact strengths and weaknesses. Advanced algorithms prioritize this inventory based upon the demands of the situation -- in this case, the skills tested on the GMAT -- and present you with the particular materials (text, video, practice items, skills quizzes, supplemental lessons, etc.) that will most efficiently increase your score. Add in the best teachers and the flexibility of team teaching, and you'll start to see the full package.
We have some student testimonials on our website, and you can dig up a little information about us here on the BTG forum as well, but the fact is that Knewton was born in early 2008. However, the people who work for Knewton are definitely not new to test prep. I personally have more than 15 years of experience in the standardized testing industry; the two experts who built the GMAT algorithms work for Knewton, and our teachers are among the best anywhere. So even though Knewton itself is new, the people who work for Knewton are veterans.
I bring that up because the discussion of score improvement always sounds self-serving. We've certainly had students with tremendous increases, but most companies with lots of students have at least a few cases they can point to of great results. But those results don't really speak to the opportunity you have individually, so what we do provide is a Money-Back Guarantee of at least 50 points improvement. The sky can be the limit, but we wouldn't offer this guarantee if we didn't have confidence in our service. The ultimate results lie in the motivations of the student, but we believe we have a program that enables true success.
Given your timeline and the amount of time you can put in, you have a good shot at a significant score increase, though I'm not sure what your goal is. However, I wouldn't recommend that intensive of a study plan. While time is certainly a key factor, quality of study is perhaps even more important (you'll see that message again and again on these boards). You have to be doing things that get to the heart of your performance, and simply doing a million practice problems won't necessarily accomplish that. I happen to think we have some of the most innovative strategies in the industry today, but beyond that we have thousands of questions at your fingertips -- and the adaptive engine will ensured you are served questions that target your key areas of need.
As for the discount you asked about, the $20 difference is actually the rebate you get from BTG. You can find the instructions to get it here:
https://www.beatthegmat.com/how-to-get-k ... count.html
Hope that adds some insight.
Best,
Jose