Can somebody comment on the durability of the sigma design? It feels like there is just sooo much stress put onto the exact center of the leading edge....

No issues with durability, at least with my kites.

No problems with durability. On my local beach first generation Helixes are still flying. My buddy still flies his Cult from the second year they came out, and he has put that kite through hell and back.

Sigma kites are rock solid, the torch although has issues with the leadind edge exploding I hope Naish have resolved the issue with the Torch as it is the best C kite out there.

As for the new kites the one pump system is so easy to repair now with the new location of the zipper on the struts well done by far now the easiest and cleanest one pump system on the market.

I had 3 generations of helix with zero problems, extremely well built and took a lot of crashes. I have never seen one that has been ripped.

I use mine for teaching and have had no issues, kites still solid.

wow sweet. thanks everybody.

I use them over four years. No problems so far.