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

Execution · Pure Mechanics
A fast-paced military shooter where twitch aim against other players is the core test.

Execution · Pure Mechanics
A fast arena shooter where twitch aim and movement against human opponents is everything.
Call of Duty: Modern Warfare 3 leans Execution (Pure Mechanics); Unreal Tournament 2003 leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 3
aim and reflexes decide most engagements
Unreal Tournament 2003
aim and movement speed decide duels
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 3
predicting human opponent positioning and habits
Unreal Tournament 2003
predicting human opponent positioning
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 3
spawn placement and loadout drops vary
Unreal Tournament 2003
weapon and pickup spawns vary
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 3
loadout tuning and map knowledge help
Unreal Tournament 2003
map control and item timing 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.