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 · Grand Arena
A combo system built on constant Combo Breaker mind-games that create a unique adaptive read-off at every moment of a combo.

Reads · Competitive PvP
A parry system that elevates reads to the central skill axis, with execution demands that remain punishing decades later.
Killer Instinct (2013) leans Execution (Grand Arena); Street Fighter III: 3rd Strike leans Reads (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Killer Instinct (2013)
Shadow counters and Combo Breaker timing demand very precise inputs
Street Fighter III: 3rd Strike
SA combo links and precise parry timing set an extreme execution ceiling
Street Fighter III: 3rd Strike leans a little harder on reads, though the gap is small.
Killer Instinct (2013)
Combo Breaker prediction is a pure read-off against an adaptive opponent
Street Fighter III: 3rd Strike
Parry is a pure real-time read against an adapting human - the defining mechanic
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Killer Instinct (2013)
No RNG; all mechanics are fully visible
Street Fighter III: 3rd Strike
No RNG; all information is transparent
Killer Instinct (2013) leans a little harder on optimization, though the gap is small.
Killer Instinct (2013)
Instinct activation timing and optimal opener routes are well-studied
Street Fighter III: 3rd Strike
Super Art selection and character punish routing are well-studied
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.