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
Chaotic tag fighter whose top tiers reward blistering execution and assist mastery.

Execution · Grand Arena
Frame-perfect execution fused with constant prediction of an adapting human opponent.
Marvel vs. Capcom 2: New Age of Heroes leans Execution (Grand Arena); Ultra Street Fighter IV 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.
Marvel vs. Capcom 2: New Age of Heroes
infinite combos and assist timing demand elite hands
Ultra Street Fighter IV
One-frame links and FADC timing set a brutal hands ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom 2: New Age of Heroes
humans bait assists and mix high-low constantly
Ultra Street Fighter IV
Footsies and conditioning the human opponent is the core duel
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom 2: New Age of Heroes
fully deterministic engine
Ultra Street Fighter IV
Almost nothing hidden once both characters are known
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom 2: New Age of Heroes
team order, assist synergy, and matchup knowledge
Ultra Street Fighter IV
Frame data, matchups and option-selects form deep studied theory
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.