Theoretically a Kite powered vehical should be able to tack upwind, but in practice the kite boarders can't to any significant measure. At least not the ones here at Zandvoort and they are a pretty darn active and moneyed bunch. Each year they buy several new sets.

I'm told formula sailboards can actually point pretty high and as such I don't see the kite boarders outpoint them by 15 degrees.

In the end of the day a kite will always be less efficient aerodynamically then a (masted) rig. This is also the experience I have with power kites that I have build myself. Their power quickly decreases when they reach the "zenith". A quality that one needs for good upwind work.

Summurized, I can not smooth my own observations with those presented by you. Naturally this can just as easily point to an oversight on my side of the argument.

Wouter