I was warned to be careful. My friend told me that cliff's relies too much on the big picture and explaining important topics. Isn't DAT bio more obsure-detail oriented? Like asking you to track plant development on the cellular level or something. Schaum's is INCREDIBLY boring and annoying, but if what a lot of test-takers have been telling me is correct, you really need to memorize random details. Raven's Bio, as well as campbell's bio are both good in terms of detail. I think if you memorize these textbooks back to back, you should be good for the exam. Best of luck!