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.

Execution · Grand Arena
A hyper-fast tag fighting game defined by three-character teams and touch-of-death combos.
Killer Instinct (2013) leans Execution (Grand Arena); Ultimate Marvel vs. Capcom 3 leans Execution (Grand Arena).
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
Ultimate Marvel vs. Capcom 3
Long touch-of-death combos demand elite hands
Killer Instinct (2013) 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
Ultimate Marvel vs. Capcom 3
Mixups and assist baits versus adapting humans
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
Ultimate Marvel vs. Capcom 3
Almost fully deterministic
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
Ultimate Marvel vs. Capcom 3
Team composition and matchup knowledge run deep
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.