I used to race gokarts with 2 strokes and to run reliably and fast I had to replace the ring each meeting, piston and ring each second meeting and piston, ring and rod each fourth meeting so I'm a bit wary of 2 strokes. I'm sure that's not necessary for these but -

How often do they need a rebuild ?

How often are you swimming to shore with a ski that won't go?

How long will it go on a tank of fuel?