I just recently finished the Kaplan DAT course. Overall, it is all review about what you have learned in undergrad science courses. The course also teaches you how to take DAT with their methods. I personally needed it because I graduated from college two years ago so I need those type of basis to get back on track. The course may also help you to get a little more motivated if one is a lazy bum like myself. The course itself is quite expensive. There's also Kaplan Online DAT courses, slightly cheaper. The online practice materials (full-length tests, workshops, and quizzes) are helpful (but i haven't take the DAT yet so can't compare Kaplan to the real DAT).
Even taking Kaplan classes you still will need to study on your own. The classes are really just for review and maybe a couple tips here and there (i.e. for PAT). At the end, it is really up to oneself to practice questions and read the materials. As many others here on SDN would suggest to get as much study materials as you can. Study aids such as Destroyer, Crack DAT PAT, TopScore, ACS, etc. They all will help in their own way. And yes, they are much cheaper than Kaplan courses.
