There is also a section devoted to mdt and hdt haulers on the sister forum to this one,
iRV2 Forum | - RV Forum Community and RV News, also check out the hdt rally site, and escapees, all have good info on hdt's. I tow with an mdt and would never go back to a dually, and will likely move up to a singled hdt for my next truck. Braking, grades, curves, weight handling, all the things that can keep you on the edge of your seat in a dually go away with a big truck. But they are not for everybody.