If you used Cliffs AP Bio for the DAT, did you do the full exams at the end of the book? If so, did you think the questions were relevant, too easy, or too hard, out of scope?
I haven't taken the DAT yet, but I've gone through Cliffs and the practice questions in the back of the book are a pretty quick run-through, so why not just do them...you can never be too prepared for bio.