head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

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

Execution · Competitive PvP
Definitive competitive tactical FPS balancing aim mastery with team strategy.
Call of Duty: Modern Warfare 3 leans Execution (Pure Mechanics); Counter-Strike: Global Offensive leans Execution (Competitive PvP).
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
Counter-Strike: Global Offensive
Spray control and flick precision at the top
Counter-Strike: Global Offensive leans a little harder on reads, though the gap is small.
Call of Duty: Modern Warfare 3
predicting human opponent positioning and habits
Counter-Strike: Global Offensive
Anti-stratting and mid-round adaptation
Counter-Strike: Global Offensive leans a little harder on variance, though the gap is small.
Call of Duty: Modern Warfare 3
spawn placement and loadout drops vary
Counter-Strike: Global Offensive
Information hidden until contact
Counter-Strike: Global Offensive leans a little harder on optimization, though the gap is small.
Call of Duty: Modern Warfare 3
loadout tuning and map knowledge help
Counter-Strike: Global Offensive
Utility lineups, economy, and default strats
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.