Performance
With that kind of horsepower, both the Ford Expedition and the Nissan Armada are legitimate sportscars.
Drivetrain
The Ford Expedition's engine is slightly smaller than the Armada's, but not terribly so.
The Ford Expedition has no lessons to learn regarding pickup from the Nissan Armada.
Utility
Neither the Expedition nor the Nissan Armada has a marked advantage with respect to seating capacity.
The Ford Expedition is likely a better choice than the Armada with respect to transporting cargo, especially if you often need to carry a lot of gear or sizeable dogs.
There's little the Ford can tow that the Nissan Armada cannot.
Comfort
Taller drivers will significantly enjoy the extra head room in the Nissan Armada's front cabin compared to the Ford Expedition.
The ampler interior dimensions of the Armada make it roomier for your passengers than the Ford.
Dimensions
The Ford Expedition and the Nissan Armada compete for the same parking spaces.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. The Nissan Armada is considerably cheaper to get to the dealership than the Ford Expedition.
With respect to MSRP, the Nissan Armada costs almost as much as the Ford (though the Ford is a bit cheaper).
Warranty
The Nissan Armada and the Expedition have the same basic after-sale protection.