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 · Competitive PvP
Twitch ball control plus constant prediction of human defenders on known maps.

Execution · Pure Mechanics
A simulation tennis game built around precise shot-timing rallies.
TagPro leans Execution (Competitive PvP); Top Spin 4 leans Execution (Pure Mechanics).
Top Spin 4 leans a little harder on execution, though the gap is small.
TagPro
Ball handling, boosts and juke precision decide grabs
Top Spin 4
Shot timing meter decides every rally
TagPro leans a little harder on reads, though the gap is small.
TagPro
Human defenders adapt to your routes every match
Top Spin 4
Human PvP rewards anticipating placement habits
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
TagPro
Maps and power-up timers are fully visible
Top Spin 4
Almost no randomness in ball physics
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
TagPro
Map routes, button plays and power-up timing are studyable
Top Spin 4
Player builds and court tactics are learnable
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.