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

Execution · Practiced Mastery
Isometric movement control while herding Flickies along memorised routes.

Execution · Practiced Mastery
One-thumb tap-timing precision over fixed courses with solvable coin routes.
Sonic 3D Blast leans Execution (Practiced Mastery); Super Mario Run leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic 3D Blast
Isometric momentum control and Flicky herding need precise movement
Super Mario Run
One-handed tap timing for coin lines demands precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic 3D Blast
Robotnik bosses run fixed patterns
Super Mario Run
Auto-runner with no adaptive opponent; Toad Rally is asynchronous
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic 3D Blast
Flicky and badnik placements never change
Super Mario Run
Courses are fixed and fully learnable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic 3D Blast
Routing each zone for Flickies and emeralds is learnable
Super Mario Run
Routing perfect coin runs is a solvable layout puzzle
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.