904 Clutchflite

Well...they were heavier and more complex than other solutions, like the Lenco.
It could also be argued they are the worst for 'drivetrain abuse' as you can get a full RPM, full power shift without any of the cushioning effects of a torque converter.

The best description I've heard is from a guy in Chicago who sold me a couple he had. He said, "When you hit go from first to second gear, it's like God reached down and smacked you in the ***..."