I had the chance to try the Zephyr in 9-10 knot cold wind with monster door, flat water, this was minimal condition for me, i am a lightwind and kiterace freak with 19 Silverarrow ect. but normally riding tubes
My thoughts : great tube kite, very easy, feels light, wont back stall, super stable, quick turning, i could easily do low jump kiteloop with monsterdoor ( never had so much fun in 10 knot )
I could go maby 10 degrees upwind in that condition, i compaired many times to my 12m speed2
and the Zephyr has more grunt and was easier to get up and plane but it didnt accelerate in the apparent wind, similar to most tubes, the 12m speed2 was more difficult to handle in the low wind ( this 12m is the normal heavy fabric ) but when the apparent wind kicked in i was going faster and more upwind than Zephyr it just felt like the wind was stronger every time i changed kite, that said the zephyr is was much easier to use especially for a tube rider
There are to many varibles to conclude anything from this, but i had great fun with both i also looped the speed for the first time.. wuuush
Mike