head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Competitive PvP
The definitive classic Street Fighter II revision and a founding tournament fighter.

Execution · Competitive PvP
A combo-heavy 3D fighter where lab-trained hands meet live human prediction.
Super Street Fighter II Turbo leans Execution (Competitive PvP); Tekken 6 leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Super Street Fighter II Turbo
One-frame links, charge timing, and strict motions
Tekken 6
Bound combos and movement push a high physical ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Super Street Fighter II Turbo
Footsies and throw mixups against an adapting human
Tekken 6
Rage comebacks amplify the human guessing game
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Super Street Fighter II Turbo
Minor damage variation; everything else visible
Tekken 6
Visible state; nothing meaningfully random
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Super Street Fighter II Turbo
Matchup knowledge and super meter spend are studied lines
Tekken 6
Optimal bound routes and punishment charts are lab work
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.