I have the covercraft Weathersheild HP. It is very light and virtually dust tight. The pros of the lightness is its easy to put on and off in calm winds, and folds up nice and small for storage. If its breezy, it can be a little tricky to put on. I use a bungee cord to keep it on the car and never had a problem with it coming off. It can also be washed in a household washing machine.
I had the NOAH, and in direct sunlight only lasted a few years (it was warranteed) and it was not dustproof, so whenever I would remove it, my car was covered in dust / dirt. It would also get completely saturated when it rained, and being thick it would take longer to dry.
The benefit is it could offer more protection against dings and or objects hitting the car due to its thickness.