I've used it. Don't get the study guide! It's not worth it at all. I never used it. I would get the practice questions ("tests") from morrison media though. They aren't in test form (which is a bummer) but there are A LOT of practice questions. Those helped me out way more than OAT Achiever did. It just gave me lots of practice that was helpful. But yes, they are a real company and reputable. I can't seem to find the link to the practice questions though....