head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; Jagged Alliance: Rage! demands more variance.

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

Optimization · Pure Optimization
A turn-based mercenary tactics game about positioning and resource management.
Fallout: New Vegas leans Optimization (Pure Optimization); Jagged Alliance: Rage! leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Jagged Alliance: Rage!
Turn-based, so no aim or reflex demand
Jagged Alliance: Rage! leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
Jagged Alliance: Rage!
Enemy AI is scripted, not adaptive to you
Jagged Alliance: Rage! leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
Jagged Alliance: Rage!
Hit chances and ambush placement add randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Jagged Alliance: Rage!
Positioning, action-point use and gear management decide fights
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.