It's generally not the legs that bend (on the good EZ-Ups). The weak point is what's called the "outer truss". These components are the X braces that span from the top of one leg to another. On some models there are two of these X's per side, and on some there are three. The middle point of the X, where two bars meet and are held together with a couple squarish plastic pieces and a bolt through them, is far and away the weakest part of the structure. These can easily get bent if someone is just a little rough setting it up or tearing it down. And once they have a small bend/crease in them, it's just a matter of time, and a little bit of wind, until they fail completely. Comparitively the legs are bombproof.
If EZ-Up could engineer this component better somehow, and beef up this major weak point, they would have a vastly superior product. As it is, their's is the best on the market (in their class), but it's still a lousy design. Everyone else's, as far as I know, is even worse.
s6