For me right now.... i am simply used to allowing my manual down shifting and exhaust brake to take care of a large percentage of braking for me, luckily the banks exhaust brake i have on this 5.9 is a monster when your able to downshift yourself. However the one that was on my 6.7 dually was quite effective as well. All in all the braking while important should be miniscule between the two vehicles, i would still vote for dually having more breaking ability. The used truck market is not in a purchasers favor at the moment thought that is for certain!