Power & top speed
110cc quads make ~6bhp and top out around 45km/h. 125cc quads like Toodles make ~7.5bhp and top out around 60km/h — with the limiter fully open.
Rider size
110cc suits riders up to about 150cm. 125cc suits riders 130cm+ and grows with them into their teens.
Resale
125cc quads hold value better on the used market thanks to broader demand.