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 70s-cinema getaway driving game with famously demanding physics.

Execution · Pure Mechanics
The last mainline Guitar Hero, wrapping its setlist in a quest with score power-ups.
Driver leans Execution (Pure Mechanics); Guitar Hero: Warriors of Rock leans Execution (Pure Mechanics).
Guitar Hero: Warriors of Rock leans a little harder on execution, though the gap is small.
Driver
Handbrake control and pursuit driving by feel
Guitar Hero: Warriors of Rock
Expert charts and the brutal 2112 finale
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Driver
Police AI is mappable
Guitar Hero: Warriors of Rock
Nothing adapts
Driver leans a little harder on variance, though the gap is small.
Driver
Traffic adds mild unpredictability
Guitar Hero: Warriors of Rock
Deterministic charts
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Driver
City routes and mission tactics learnable
Guitar Hero: Warriors of Rock
Power-up choices and star power routing
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.