I trained for AN/DP with Duane Johnson (ppodiver on here - www.precisiondiving.com) and would highly recommend him. Great skills in the water, he sets the example of how one should dive at the tec level, fantastic presentations and the ability to deliver in a way the student needs to see to be able to understand. He really pushed us to be better divers and increase our envelope of comfort and our ability to deal with potential problems. He went way beyond the course standards and I really appreciate that.
BTW I didn't pass the first time through - I went to practice some skills for a few months and did a few more dives to earn my card.
+1 on this comment.
I did Advanced Nitrox/Deco with Duane a few years ago. He really does put time and energy into making the best divers out of his students. His 'trademark' phrase is that he produces 'thinking divers.' One that can understand what's happening before, during, and after the dive. Very simple philosophy that gets lost in training a lot.
In terms of his class - it's intense. I believe we did ~twice the amount of dives 'required' by the agency. You dive until you're ready to advance. Duane doesn't sugar coat any feedback, but he does provide how to resolve whatever issue the feedback is being delivered on. He includes all of the course requirements, plus throws in extras like line work. He focuses on team centric diving.
If you are in the midwest and looking for tech instruction, take the time to talk with and dive some with Duane.