Well.... I'm sure the instructor has a lot to do with the quality of the course but a big part of me would prefer to take an "advanced" wreck penetration course from a thoroughly technical agency. PADI and TDI grew from very different roots and intuitively (and perhaps irrationally) I would trust TDI's methods more.
I don't know if that's rational at all. It's just an opinion.
R..
I would think be that most PADI technical instructors have wide backgrounds in how they reached that point in their lives. The same is true of most technical instructors I know. I myself have technical training from 5 agencies. The PADI program is only new in that it is their name. It was called DSAT before PADI took it over.
Here is just a bit from my own experience.
1. My own original tech experience was through TDI. The instructor made it clear from the start that he had GUE/DIR training and we would be following the GUE curriculum instead of the TDI curriculum. After a while he said that we had finished TDI standards a while ago, but he was going by the standards of a more advanced GUE course and would not be certifying us for TDI until we completed those GUE requirements. Frustrated, I contacted TDI and learned they had no problems with that at all.
2. I crossed over to UTD for a while with their strict DIR approach, after which I went back to TDI to complete my trimix training with a different instructor in a different state. He had no idea what the GUE or UTD curriculum was. He did not know squat about DIR and didn't care. We did the TDI curriculum strictly.
3. I later spent several days in Cozumel tagging along with a PADI trimix class. (I saved a lot of money that way.) Although the instruction was by no means strictly DIR in its approach, and the instructor actually made some jokes about it, it was much more DIR in its attitudes and requirements than my advanced TDI courses. It was
extremely thorough.
4. When I got my cave training from NSS-CDS, I also got a PADI Cave Diver certification, which many people do not know even exists. The requirements were just about the same as for NSS-CDS. That instructor could have given me certifications from a variety of agencies.
Consequently, I really think you have to go with the instructor more than the agency in this case.