I got a 20 on TS in all 3 achievers, and did way better on the real DAT. I don't know if it was because the practice problems helped me review the material or because it was much harder. I think that the DAT was more basic than achiever. I studied a ton for hormones and classification of animals and I had no hormones and a super easy classification question. Achiever is good to get a sense for time management and to motivate yourself to study.