Ok I am different just ask a couple of guys on this site.
I am towing a 34RL Cedar Creek 5th wheel with a 2500 SRW, 6.7L Mega Cab with 3:73 gears, a Smarty S67 set on CatCHER level 3, with the total combined weight of 20,500 LBS. I do not carry any water or waste water in the holding tanks when towing just food and cloths plus camping gear. I have towed this trailer in Colorado on I70 going west to Utah. With no issues in 5th gear, my boost was under 30psi, EGT's were under 900F , transmission temps were in the 190's and engine RPM was around 1800. The exhaust brake was on and the truck and trailer handled this load.
I have towed out east in the NC up and over Black Mountain on I40 with the same results and my truck worked great.
Now if you are looking to buy than yes buy a 3500SRW with the AISIN transmission but a 2500 can handle the towing challenges too.