I am rapidly (year to 2 year MY time frame)getting the feeling that this pairing (high torque diesel motor to Aisin TR-80 SD, 8 sp A/T) is probably one of the best in a very long time.
More on topic is that on some other references I had read, our specific transmission has a 627 # ft of torque handling capacity for our 406 # ft motor. To me this is a HUGE advantage. Many high hp/torque motors are paired with transmissions with very little safety factor.
Again off topic, I am also curious about the competitors A/T's: BMW X5 and MB ML350 (bluetecs). I understand that the 2012 MB ML350 has a so called 7 sp A/T "hybrid" CVT, even as they do not advertise this very much. Indeed most references are merely 7 sp A/T. So for me, the nexus is the longer term mpg, reliability and durability, while being mated to a 455# ft torque CDI motor.
By way of background, MB has done a great job in the past by mating a high torque CDI motor to one of the (then) best A/T; a sample would be the E320/350, ML/GL 320 CDI