To be honest, and I give this advice to anyone looking at a full size truck, go out and drive them. The big three all make good trucks, as does Toyota. They all have there quirks and issues.
For our fleet, Ford and GMC trucks have been the preference for a very long time. Local dealer support was good and in service performance has been good with not much difference in costs in service. It basically came down to which brand had the truck with the mandatory equipment at a lower price. Not much else.
The advice to go with an upgraded turbo or small V8 option is good. Typically these are low cost options, deliver similar fuel economy, and make the vehicle more pleasant to drive in general. I'm not dogging the base engine options, but for a little cost, the upgrades are nice.
I also would not be afraid of aluminum. Because of higher labor on repairs, often times instead or repair, it becomes replace with aluminum. Different, but as there gets to be more and more of it out there, it is less of an issue.