I personally thought that the science part (especially biology) was way too difficult to be helpful; all it did was frustrate me. I got a 24 in biology on the actual test, and was averaging around a 16 on the Crack biology tests, so I don't think I took anything away from them. The other stuff (math, reading, and especially PAT) I found to be really helpful though. Use their PAT tests, they saved my life! Just find something else to supplement your science studies.