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
Weapon-based dueling testing spacing execution and mixup prediction against humans.

Execution · Competitive PvP
The 3D fighting series opener where execution and human mind-games decide every round.
SoulCalibur III leans Execution (Competitive PvP); Tekken leans Execution (Competitive PvP).
Tekken leans a little harder on execution, though the gap is small.
SoulCalibur III
Spacing, movement and just-frame timing demand real hands
Tekken
Frame-tight inputs, juggle combos, movement demand trained hands
Tekken leans a little harder on reads, though the gap is small.
SoulCalibur III
Versus humans, conditioning and throw-mixup guessing decides rounds
Tekken
Human opponent adapts; throws, lows, sidesteps form mixup mind-games
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
SoulCalibur III
Deterministic combat with nothing hidden
Tekken
No hidden info; only matchup unfamiliarity early on
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
SoulCalibur III
Frame data, matchup study and stage knowledge run deep
Tekken
Frame data, punishes, and combo routing are studyable systems
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.