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

Execution · Competitive PvP
High-speed tag-team execution and human prediction in gleeful early-Versus chaos.

Execution · Grand Arena
Team hero shooter blending FPS mechanics with ability economy mind games.
Marvel vs. Capcom: Clash of Super Heroes leans Execution (Competitive PvP); Overwatch 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: Clash of Super Heroes
Chain combos, assists and infinites demand fast precise hands
Overwatch
Hero aim, movement, and ability timing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom: Clash of Super Heroes
Baiting a human's assist call or super is the duel
Overwatch
Ult tracking, flanks, and baiting human teams
Overwatch leans a little harder on variance, though the gap is small.
Marvel vs. Capcom: Clash of Super Heroes
Hidden characters aside, everything is public
Overwatch
Minor spread and matchmaking noise
Overwatch leans a little harder on optimization, though the gap is small.
Marvel vs. Capcom: Clash of Super Heroes
Team composition and infinite-combo knowledge define the meta
Overwatch
Team comps, ult economy, and positioning 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.