head to head
Mount Your Friends asks more than Wii Sports, and the gap is execution.

Execution · Pure Mechanics
Absurd physics limb control tested under a timer atop a tower of friends.

Execution · Pure Mechanics
Motion-controlled tennis, bowling, golf, baseball and boxing built around simple swing gestures.
Mount Your Friends leans Execution (Pure Mechanics); Wii Sports leans Execution (Pure Mechanics).
Mount Your Friends leans clearly harder on execution.
Mount Your Friends
QWOP-like limb control under a timer is the entire challenge
Wii Sports
Motion swing timing and accuracy decide every event
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mount Your Friends
Rivals shape the tower but climbing is solo execution
Wii Sports
Casual local opponents add light mind games
Wii Sports leans a little harder on variance, though the gap is small.
Mount Your Friends
The stack you face is visible, nothing hidden
Wii Sports
Minor physics wobble and CPU behaviour randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mount Your Friends
Grip-route planning up the pile helps marginally
Wii Sports
Simple technique tricks like bowling spin 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.