It is really going to be on how you plan to use it. I've had a PopUp camper on a 1 ton crew cab short bed and currently have a 2003 SMB RB.
Pickup Truck Pros:
1) Can separate house from truck to use truck for other purposes
2) Long wheel base for towing and road travel
3) Many trim options, electronics, drive modes, etc.
4) Can decided between diesel / gas and transmission options (at least with Ford)
1) Shorter overall length
2) Shorter wheelbase, better approach, departure, and brake over angles for off road use
3) Shorter and sloped hood for more visibility when offroad and more living space
4) With pivot seats, the cab creates open space with the living space
5) More open to the outside with big side doors and rear doors
6) For Ford's new e350 cutaway chassis, you get a 40 gallon tank.
I like the Van as I feel we can cruise on fast highways, pass when we need to, but have more capability for the places we like to go. It's just a more open feel when driving, when camping, when loading.
I did love my truck camper too. However, it was more difficult for my dog getting in and out of the truck , and yes, getting in and out of the bed
Both Options are a terrific way to go, but one will be a little better for your style and travel plans.