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
The foundational test of fighting-game execution and human prediction at speed.

Execution · Competitive PvP
The definitive classic Street Fighter II revision and a founding tournament fighter.
Street Fighter II' Turbo leans Execution (Competitive PvP); Super Street Fighter II Turbo leans Execution (Competitive PvP).
Super Street Fighter II Turbo leans a little harder on execution, though the gap is small.
Street Fighter II' Turbo
Charge timing and anti-air reactions at turbo speed
Super Street Fighter II Turbo
One-frame links, charge timing, and strict motions
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter II' Turbo
Fireball-trap mind games against an adapting human are the essence
Super Street Fighter II Turbo
Footsies and throw mixups against an adapting human
Super Street Fighter II Turbo leans a little harder on variance, though the gap is small.
Street Fighter II' Turbo
Twelve public movesets, nothing hidden
Super Street Fighter II Turbo
Minor damage variation; everything else visible
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter II' Turbo
Matchup theory and spacing fundamentals were codified here
Super Street Fighter II Turbo
Matchup knowledge and super meter spend are studied lines
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.