head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Grand Arena
Crossover fighting game where groove systems and footsies meet deep execution demands.

Execution · Grand Arena
A hyper-fast tag fighting game defined by three-character teams and touch-of-death combos.
Capcom vs. SNK 2: Mark of the Millennium 2001 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.
Capcom vs. SNK 2: Mark of the Millennium 2001
Strict links, roll cancels, groove mechanics
Ultimate Marvel vs. Capcom 3
Long touch-of-death combos demand elite hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Capcom vs. SNK 2: Mark of the Millennium 2001
Footsies and conditioning against adapting humans
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.
Capcom vs. SNK 2: Mark of the Millennium 2001
Almost no randomness in matches
Ultimate Marvel vs. Capcom 3
Almost fully deterministic
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Capcom vs. SNK 2: Mark of the Millennium 2001
Groove selection, team order, matchup theory
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.
full breakdown
Capcom vs. SNK 2: Mark of the Millennium 2001 →
full breakdown
Ultimate Marvel vs. Capcom 3 →