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

Execution · Practiced Mastery
The sequel adding Horde mode to the campaign-plus-versus cover shooter formula.

Execution · Practiced Mastery
Massive persistent-war FPS where hundreds of players contest continents simultaneously.
Gears of War 2 leans Execution (Practiced Mastery); PlanetSide 2 leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Gears of War 2
Gnasher battles and movement tech set the ceiling
PlanetSide 2
Gunplay and vehicle piloting at FPS standards
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Gears of War 2
Human opponents in versus drive prediction play
PlanetSide 2
Human enemies adapt, diluted across hundreds
PlanetSide 2 leans a little harder on variance, though the gap is small.
Gears of War 2
Horde spawns add mild randomness
PlanetSide 2
Massive battles produce constant chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Gears of War 2
Power-weapon timing and positioning are solvable
PlanetSide 2
Loadouts, terrain, and territory strategy matter
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.