It was more getting dragged for me (and the ski I used is a mahoosive thing, size of two normal skis) - had to drop one of course on top) and then it was just a slow plough before dying but just wanted to see what was possible really. I'm getting back into skiing after 15 years away but I'll stick to the local ski club and lake for that.
Kneeboarding was OK(ish) for a bit of fun with the 15. We will try more if I can ever find a 25 at the right place and price. Bought a nice used bundle last year with a fibreglass/graphite compression type kneeboard with decent edges rather than the rotomolded lump above and a reasonable wake board so need to try those.
At the end of the day it's about fun for the kids though.