head to head
Call of Duty: Modern Warfare 2 asks more than Fight Night Round 3, and the gap is variance.

Execution · Competitive PvP
Blockbuster 2009 sequel famous for killstreak chains and frantic multiplayer.

Execution · Competitive PvP
An analog-control boxing game where parry timing and feints decide versus bouts.
Call of Duty: Modern Warfare 2 leans Execution (Competitive PvP); Fight Night Round 3 leans Execution (Competitive PvP).
Call of Duty: Modern Warfare 2 leans a little harder on execution, though the gap is small.
Call of Duty: Modern Warfare 2
Fast time-to-kill rewards raw aim and reflex
Fight Night Round 3
Analog punch swings and parry timing set the skill ceiling
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 2
Outguessing human rotations and flanks
Fight Night Round 3
Versus boxing is feinting and baiting an adapting human
Call of Duty: Modern Warfare 2 leans clearly harder on variance.
Call of Duty: Modern Warfare 2
Spawn flips and killstreak randomness
Fight Night Round 3
Minor cut and stun randomness
Call of Duty: Modern Warfare 2 leans a little harder on optimization, though the gap is small.
Call of Duty: Modern Warfare 2
Killstreak economy, loadout and map knowledge
Fight Night Round 3
Stamina management and fighter builds are studyable
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.