Different characteristics of T/C's. Good question. I have ridden in trucks with ATS and DTT trannies. Since i don't own both, i don't know if i can comment on ATS without crossing the transmission line.
I will say this though, with all the high HP trucks out there running DTT's single, has anyone slipped it yet? I don't think so. So give me the best fluid coupling (DTT) and I'll still never slip lock-up. I'm happy as can be.
With all that out of the way, there is so much more to our transmissions than just a T/C. Who has the best package out there? Who does the most to make 3rd gear stronger, after all, it's weaker then the T/C anyway. How about all the other components that make things work? Do lots of research before making your decision. None of these things are cheap.
There is so much more that i would like to say, but don't know how without offending those who fall on the other side of the transmission debate. PM me if you want the full version of my story.
Later,
Chris