I bought a Ford F350 dully crew cab longbed and put a Northstar Igloo on it. It is certainly the best for me for a very specific reason- I am 6'8" tall and did not find either the Chevy or Dodge to be comfortable in the drivers seat, the Ford has better space in the driver area. I chose the Northstar because it has a 6' 8" ceiling height and I while I brush the ceiling at times at least I don't have to duck down. Most campers are 6'6" to the ceiling at best, so the best rig for a tall guy is the rig I got.
We have about 150 days in the rig, to Alaska and back to MA, then from MA to Utah, plus many small trips. If I had opportunity to buy a new rig again i think I would repeat the same purchase.
Good luck in your hunt.