TFlower
You wanted to know which one ATS or DTT.
I can tell you how I made my personal decision but you will have to decide what is important to you and what you feel comfortable with.
In the hazardous materials emergency response field I was taught to find at least three independent sources on how to handle a chemical emergency. These independent sources should agree on the behavior of the chemical and the major aspects of cleaning up the chemical release safely. The three independent source rule is great logic and a sound method for making many other decisions also. So I applied it to the process of finding a transmission vendor. The goal was to find consensus among the companies you are considering. I knew the odds of making a sound decision were in my favor if I could find three transmission re-builders who agreed on some of the controversial issues. The following two issues were important to me; your issues may be different, but the method is still the same.
1 Qualify the sources.
Which of the transmission vendors on my list actually manufacture the torque converters for the transmissions they rebuild? Which vendors only install what someone else makes for them? In my view being able to build the stuff that goes inside is a big plus.
2 Settle the torque converter clutch issue.
How many of the major transmission re-builders put more than one lock-up clutch in the torque converter? How many just have one?
How many use a billet cover?
I called four of the major transmission builders out there and found the consensus I was looking for. Then I had to decide who of the remaining three would rebuild my transmission. That decision was hard because all three remaining companies are good and build sound products.
I chose ATS because they took the time answer all my questions. They are also qualified to do the other modifications I needed. I set up an appointment, drove the truck in stock and drove it out bombed the way I wanted it. If I had to make the decision again I would go with ATS without hesitation. The transmission and torque converter have done everything they said it would do. The injectors, exhaust system, and turbo have also proven to be money well spent. The truck is way too much fun to drive.
Make your choice based on what is important to you and good Luck.
Edward