Covermytractor has the best canopies, there HDPE so limbs are no problem. You con drive over them and they pop right back to shape. The pricing is great also.
Buy the steel one from Perry. I've had a Tufftop and it was a waste of money and didn't last very long, plus it vibrated badly. Unless you absolutely don't have tree limbs and only need it for shade, I wouldn't touch a fiberglass one. I can see fiberglass getting caught and crack/break. The steel one from Perry is STOUT, doesn't vibrate/wobble and is insulated. Buy once, cry once.