Hi, my quiver is rebel 9 and R7 14.
Well I've had a great session yesterday with the 14 in about 20-25 knots Bora. what impressed me is the big air (lift) attitude and the incredible hang time, you won't belive how long you gonna float in the air with it.
The bar pressure is a little strong, but I'm habit to this and I like it.
Turning speed is high, but slow if compared to the rebel 9. anyway is perfect for kiteloops rapid change of direction and in waves.
I've never tried the low end of it, but for sure it doesn't pull in less of 12 knots (I'm 84 kilos) also if you use a 100 litres windsurf board.
I think it depend from the fact that it generates power by pulling the bar and let it in the wind window (like first crossbow did) if you let it go up and down like C kites id doesn't generate power.