head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Pro Basketball Manager 2017 demands more variance.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
A basketball team management simulation game.
Portal leans Optimization (Pure Optimization); Pro Basketball Manager 2017 leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Pro Basketball Manager 2017
management sim, no physical execution ceiling
Pro Basketball Manager 2017 leans clearly harder on reads.
Portal
No adversary modeling player.
Pro Basketball Manager 2017
opposing managers create light adaptive pressure
Pro Basketball Manager 2017 leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Pro Basketball Manager 2017
match simulation involves random rolls
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
Pure puzzle-solving optimization.
Pro Basketball Manager 2017
roster and tactics optimization is the core loop
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.