head to head
Mario Kart 8 asks more than Sonic & All-Stars Racing Transformed, and the gap is variance.

Execution · Twitch Chaos
A kart racer where controlled chaos from random items tempers otherwise precise driving skill.

Execution · Twitch Chaos
Kart racing execution moderated by item randomness and learnable track routes.
Mario Kart 8 leans Execution (Twitch Chaos); Sonic & All-Stars Racing Transformed leans Execution (Twitch Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Kart 8
precise drifting and item timing matter
Sonic & All-Stars Racing Transformed
Drift timing and transforming vehicle control reward practice
Sonic & All-Stars Racing Transformed leans a little harder on reads, though the gap is small.
Mario Kart 8
minimal, mostly reacting not predicting
Sonic & All-Stars Racing Transformed
Human racers add light positional mind games
Mario Kart 8 leans clearly harder on variance.
Mario Kart 8
item boxes are heavily randomized
Sonic & All-Stars Racing Transformed
Item rolls regularly upend race positions
Mario Kart 8 leans a little harder on optimization, though the gap is small.
Mario Kart 8
track lines and item strategy solvable
Sonic & All-Stars Racing Transformed
Track shortcuts and drift-boost routes 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.