BTS (Brians Truck Shop). There are none that get any any better than Brian's trannys.
Brian had a guy with a 12 second Cummins in a Superduty F-350 basically acting as a test mule for his trannys. With that much horsepower, the guy managed to break the 4R100 many times. But everytime it broke, Brian would tear it apart, figure out what broke and improve it so it wouldn't break again. I think it eventually got to the point where the only thing breaking was the custom made adapter input shaft that allowed the Cummins to mate with the 4R100.
I've had one for I'm guessing 7 or 8 years and 130,000 or so miles. I haven't been able to break it yet.