Because you stated that you are getting ready to take the DAT for the 3rd time, I highly recommend that you take the class-room DAT class. You CANNOT afford to have a 3rd mediocure performance. I'm under the impression that you had two prior mediocure scores, otherwise you wouldn't taking the DAT for the 3rd time.
Keep in mind that I am a Kaplan DAT instructor.
Here's the reasons why you should take the live class:
1. You get to ask the instructor specific questions about problems you are having, and about topics you're stuck on. I usually stick around after class for about a 1/2 hour to answer questions for the students. Also, during class, I can tell when something went over a student's head. When that happens, I try to clarify the topic for him/her right after class.
2. PAT is very hard to learn online or in a book if you have scored low in the past, i.e. less than 17. PAT needs to be explained by a live instructor since he or she can explain the concepts in several different ways by drawing examples in front of you with detailed explanations. It is extremely difficult to explain PAT concepts in writing.
3. There a ton of QR and Gen Chem tricks that are easier to learn when a live person tells it to you in person versus reading about them. In addition, if you don't get the math trick, you can ask the instructor right there and then to explain it to you in a different way. That will never happen online.
4. You already proved that you are not getting a stellar DAT performance on your own terms. Accept that you need help from another person and from a differnt point of view of why you're missing certain questions and topics.
Look, I have read a ton of SDN threads about how some Kaplan instructors suck. But remember, if you feel that you got a crappy instructor, complain to the Kaplan Office, and they will get you enrolled into another class with a different instructor. You will eventually get an instructor that will make a difference.
Good luck.