People say CDP is fairly accurate with the real DAT as far as I know. I could be wrong.
However, I have a DAT Barron's book and I found many errors within the book pertaining to the DAT itself, some wrong molecular formulas (ie. glucose is written as C6H12C6). Also, many said that the answer key for the practice tests are wrong. However, Barron's is okay with the PAT portion strategy wise but the actual practice is way easier than the actual DAT. You're better off with a Cliff's book. You can also get Kaplan Blue Book as an alternative.
My advice stay away from Barron's.