The fact that it's well designed and constructed.
However, it won't hold up in a strong wind either. I don't think that's the intent of these things. They're for convenient shelter from the sun and light rain. Not hurricane Katrina.
Thats what I am saying!...sorry I was being a little facetious in the other post. Its something to use if its starts raining a little or to keep the sun off your back. If the PVC elbows break, well then, they break and you go get some more...no biggie.
x2 on what Musky said, I would find me some long bugee cords and go corner to corner to support the tarp.
You know what would be slick if you did it right is if you could get an old projector screen that rolls up in a housing and replace the screen with a waterproof canvas/whathaveyou...just use it for the rolling mechanism. I see people throwing them out all the time. Or maybe thats just the redneck in me coming out in that idear.