head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, and it is a single point.

Execution · Competitive PvP
Anime fighter debuting the Drive system and famously execution-heavy cast.

Execution · Grand Arena
Frame-perfect execution fused with constant prediction of an adapting human opponent.
BlazBlue: Calamity Trigger leans Execution (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.
BlazBlue: Calamity Trigger
Long anime combos and tight defensive inputs
Ultra Street Fighter IV
One-frame links and FADC timing set a brutal hands ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
BlazBlue: Calamity Trigger
Human opponents demand constant conditioning and adaptation
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.
BlazBlue: Calamity Trigger
Negligible randomness in matches
Ultra Street Fighter IV
Almost nothing hidden once both characters are known
Ultra Street Fighter IV leans a little harder on optimization, though the gap is small.
BlazBlue: Calamity Trigger
Frame data, drive mechanics, and matchup study
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.