I used to have a 12m 05 bronco which I really liked then bought a 12m One in the spring, after 6mos still smiling.
It boils down to what you want; If you are a kitelooping unhooking handle passing to blind kind of guy then you are probably better off with the diablo or bronco.
If you are like me, jump as high as you can, backloops, grabs etc and 41 yrs old with shot knees then the One is the kite for you.
I will sum it up;
Wind range: One hands down, I weigh 15 stone (200+lbs), 12m One with a big board (flydoor) 12-14 mph (boring, don’t get the appeal personally). To really have fun 17ish+ mph-low 30’s. I have used it when it picked up to a little over 40 but it was just hanging on.
Relaunch, bronco with 5th line and One are about same, dead easy.
Jumping: Huge floaty jumps with the one.
Upwind: both are easy but the one goes upwind further, but to get the most out of the one you need a very fast board as it flies more on apparent wind.
Gusts: One no contest, just sheet in and out, it eats them, bronco lots of ass dragging foot stomping.
Turning speed: Probably the 12m bronco, the One being so flat requires a very different technique. More like flying an ozone frenzy, lovely kite but different., you need to sheet out as it turns
Waves: Flat kites for sure, the ability to power up to get on a wave, sheet out, ride the wave, power up, scoot off as it crumbles and find another. The nuts.
Hope that helps