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
Pure aim and movement skill tested against adaptive human opponents competing for spawn-cycle dominance.

Execution · Pure Mechanics
A fast arena shooter where raw aim and movement meet item-control strategy.
Quake III Arena leans Execution (Pure Mechanics); Unreal Tournament 2004 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.
Quake III Arena
Rail and rocket aim at speed is the entire game
Unreal Tournament 2004
Aimbot plus perfect dodging trivializes arena duels
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Quake III Arena
Human opponents adapt their routes and timings in direct response
Unreal Tournament 2004
Predicting human movement and timing in duels matters
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Quake III Arena
Spawn locations have mild randomness but are quickly mapped
Unreal Tournament 2004
Spawns and item timers are knowable, little hidden
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Quake III Arena
Armor and weapon timing routes are learnable and highly leveraged
Unreal Tournament 2004
Item timing, map control, and weapon economy are studied
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.