head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Competitive PvP
Striking execution and constant human mix-up prediction across MMA phases.

Execution · Competitive PvP
High-speed tag-team execution and human prediction in gleeful early-Versus chaos.
EA Sports UFC 5 leans Execution (Competitive PvP); Marvel vs. Capcom: Clash of Super Heroes leans Execution (Competitive PvP).
Marvel vs. Capcom: Clash of Super Heroes leans a little harder on execution, though the gap is small.
EA Sports UFC 5
Strike timing, head movement and transition denial demand hands
Marvel vs. Capcom: Clash of Super Heroes
Chain combos, assists and infinites demand fast precise hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
EA Sports UFC 5
Out-guessing a human's strike-grapple mix is the core duel
Marvel vs. Capcom: Clash of Super Heroes
Baiting a human's assist call or super is the duel
EA Sports UFC 5 leans a little harder on variance, though the gap is small.
EA Sports UFC 5
Damage events and doctor stoppages add chaos
Marvel vs. Capcom: Clash of Super Heroes
Hidden characters aside, everything is public
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
EA Sports UFC 5
Stamina math and matchup study underpin the meta
Marvel vs. Capcom: Clash of Super Heroes
Team composition and infinite-combo knowledge define the meta
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.