head to head
Neither is simply harder - they are hard in different places. FIFA Manager 14 demands more variance; Portal demands more execution.

Optimization · Pure Optimization
A football management sim testing squad-building, finance and tactical optimization.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
FIFA Manager 14 leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
FIFA Manager 14
Menu-driven management, no physical input skill
Portal
Portal placement timing modest.
FIFA Manager 14 leans clearly harder on reads.
FIFA Manager 14
AI clubs follow scripted logic, no real adaptation
Portal
No adversary modeling player.
FIFA Manager 14 leans clearly harder on variance.
FIFA Manager 14
Match results and injuries carry simulation randomness
Portal
Deterministic chambers; no randomness.
FIFA Manager 14 leans a little harder on optimization, though the gap is small.
FIFA Manager 14
Squad, finance and tactics planning dominates entirely
Portal
Pure puzzle-solving optimization.
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.