I took the Kaplan course, which includes the subject tests, flashcards, online workshops, online quizzes, review notes, lesson book, CD and the class itself. I think the Kaplan review note and the Blue book also have slightly different formats since the review note does not contain practice DAT at the end. Instead they just have like 10-15 questions in the end of each chapter. The review note also does not contain PAT section.
I also used Achiever and Topscore, and made sure that I understand whats going on, regardless if I get the question right or wrong. Achiever was pretty helpful, esp. the PAT section. I know some people think that it is way too difficult and does not represent the actual test - but I think after going through those problems, the actual PAT will be a breeze.
I enrolled in the Kaplan course, which was 1300. In my opinions, I think that it was quite overpriced. To tell the truth I think the whole course probably worthed around 600. The good thing about it is they actually provide you with extra questions, and that is always good. Kaplan has around 4-5 full lengths DAT, and I didn't think they were that easy.
The bio from Kaplan def. needs to add A LOT of additional info, since about 50% of the stuff that I was tested was actually not on Kaplan. OC and GC from Kaplan is pretty solid and should you understand all those reactions, you will be good to go for OC and GC on the actual DAT.
Hope it helps.