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

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.

Execution · Practiced Mastery
A modern-war reboot following Tier 1 operators in Afghanistan.
Grand Theft Auto V leans Execution (Practiced Mastery); Medal of Honor (2010) leans Execution (Practiced Mastery).
Medal of Honor (2010) leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Medal of Honor (2010)
Modern gunplay in campaign and multiplayer
Medal of Honor (2010) leans a little harder on reads, though the gap is small.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Medal of Honor (2010)
Competitive MP adds human prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Some mission and lobby randomness.
Medal of Honor (2010)
Scripted campaign, modest MP randomness
Medal of Honor (2010) leans a little harder on optimization, though the gap is small.
Grand Theft Auto V
Heists, money loops, builds learnable.
Medal of Honor (2010)
Loadouts and map control are learnable
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.