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 · Pure Mechanics
The last mainline Guitar Hero, wrapping its setlist in a quest with score power-ups.

Execution · Pure Mechanics
Cute two-button rhythm game where everything reduces to hitting notes on beat.
Guitar Hero: Warriors of Rock leans Execution (Pure Mechanics); Muse Dash leans Execution (Pure Mechanics).
Muse Dash leans a little harder on execution, though the gap is small.
Guitar Hero: Warriors of Rock
Expert charts and the brutal 2112 finale
Muse Dash
Two-lane rhythm hits at high BPM are pure hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Guitar Hero: Warriors of Rock
Nothing adapts
Muse Dash
Charts never adapt
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Guitar Hero: Warriors of Rock
Deterministic charts
Muse Dash
Fully deterministic note charts
Guitar Hero: Warriors of Rock leans a little harder on optimization, though the gap is small.
Guitar Hero: Warriors of Rock
Power-up choices and star power routing
Muse Dash
Character buffs and chart memorization help margins
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.