head to head
Street Fighter III: 3rd Strike asks more than Ultra Street Fighter IV, and the gap is reads.

Reads · Competitive PvP
A parry system that elevates reads to the central skill axis, with execution demands that remain punishing decades later.

Execution · Grand Arena
Frame-perfect execution fused with constant prediction of an adapting human opponent.
Street Fighter III: 3rd Strike leans Reads (Competitive PvP); Ultra Street Fighter IV 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.
Street Fighter III: 3rd Strike
SA combo links and precise parry timing set an extreme execution ceiling
Ultra Street Fighter IV
One-frame links and FADC timing set a brutal hands ceiling
Street Fighter III: 3rd Strike leans clearly harder on reads.
Street Fighter III: 3rd Strike
Parry is a pure real-time read against an adapting human - the defining mechanic
Ultra Street Fighter IV
Footsies and conditioning the human opponent is the core duel
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter III: 3rd Strike
No RNG; all information is transparent
Ultra Street Fighter IV
Almost nothing hidden once both characters are known
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter III: 3rd Strike
Super Art selection and character punish routing are well-studied
Ultra Street Fighter IV
Frame data, matchups and option-selects form deep studied 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.