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 · Competitive PvP
Tests shot timing and faking out human defenders amid item-driven chaos.

Reads · Competitive PvP
The Wii entry whose slower pace and infamous random tripping pushed Smash toward defensive mind games.
Mario Strikers Charged leans Execution (Competitive PvP); Super Smash Bros. Brawl leans Reads (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Strikers Charged
Timing tackles, charged shots and goalie deflections needs quick hands
Super Smash Bros. Brawl
Slower engine lowers the ceiling but spacing still needs hands.
Super Smash Bros. Brawl leans a little harder on reads, though the gap is small.
Mario Strikers Charged
Versus humans, faking shots and baiting tackles drives goals
Super Smash Bros. Brawl
Defensive bait-and-punish yomi dominates its floaty neutral.
Mario Strikers Charged leans a little harder on variance, though the gap is small.
Mario Strikers Charged
Items and stage hazards inject swingy chaos into matches
Super Smash Bros. Brawl
Random tripping injects genuine uncontrollable RNG into movement.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Strikers Charged
Captain abilities and team builds reward knowing the systems
Super Smash Bros. Brawl
Matchup knowledge and ledge play reward study within a campy 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.