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 · Competitive PvP
The foundational test of fighting-game execution and human prediction at speed.

Execution · Competitive PvP
The classic 'dream match' team fighter widely held as KOF's most balanced competitive entry.
Street Fighter II' Turbo leans Execution (Competitive PvP); The King of Fighters '98 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.
Street Fighter II' Turbo
Charge timing and anti-air reactions at turbo speed
The King of Fighters '98
Strict inputs, short hops, tight punishes
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter II' Turbo
Fireball-trap mind games against an adapting human are the essence
The King of Fighters '98
Human opponents constantly adapt and condition you
The King of Fighters '98 leans a little harder on variance, though the gap is small.
Street Fighter II' Turbo
Twelve public movesets, nothing hidden
The King of Fighters '98
Near-fully visible game state
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter II' Turbo
Matchup theory and spacing fundamentals were codified here
The King of Fighters '98
Team order and matchup theory reward study
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.