head to head
Fallout: New Vegas asks more than Final Fantasy XIII, and the gap is execution.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.

Optimization · Pure Optimization
Linear JRPG built around real-time paradigm switching and stagger combat.
Fallout: New Vegas leans Optimization (Pure Optimization); Final Fantasy XIII leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Final Fantasy XIII
Paradigm shifts need timely menu reactions
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
Final Fantasy XIII
Scripted stagger-phase bosses
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Some loot and crit RNG
Final Fantasy XIII
Minor randomness in enemy actions
Fallout: New Vegas leans a little harder on optimization, though the gap is small.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Final Fantasy XIII
Paradigm sequencing and stagger timing are solvable
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.