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

Execution · Pure Mechanics
A classic 2D Mario platformer rewarding tight jump execution above all.

Execution · Pure Mechanics
The modern Rock Band keeping plastic-instrument band night alive with a huge DLC library.
New Super Mario Bros. U Deluxe leans Execution (Pure Mechanics); Rock Band 4 leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
New Super Mario Bros. U Deluxe
precise jump and platforming execution
Rock Band 4
Instrument accuracy remains the entire test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
New Super Mario Bros. U Deluxe
fixed enemy patterns, no adaptation
Rock Band 4
No adaptive opponent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
New Super Mario Bros. U Deluxe
minor enemy placement randomness
Rock Band 4
Freestyle solos add slight improvisational looseness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
New Super Mario Bros. U Deluxe
level routing for speed/collectibles
Rock Band 4
Overdrive pathing and chart familiarity
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.