head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
The original post-apocalyptic CRPG where character builds solve the wasteland.

Optimization · Pure Optimization
Mastering faithful D&D 3.5 rules and party builds against dice-roll swing.
Fallout leans Optimization (Pure Optimization); The Temple of Elemental Evil leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
Turn-based, no dexterity
The Temple of Elemental Evil
Turn-based clicks - hands never matter
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
No adaptive opposition
The Temple of Elemental Evil
Encounters run on D&D scripts, not adaptation
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
To-hit rolls and random encounters
The Temple of Elemental Evil
Dice rolls swing fights until builds overpower them
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout
SPECIAL builds and quest routing are deeply solvable
The Temple of Elemental Evil
Mastering 3.5e rules, builds and positioning is the game
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.