I have to wonder......
I have a Weathershield car cover and it protects fairly well. My car is outside 24/7 and it was pretty dry in NY all Summer. Now with the rain starting up again and snow right around the corner, the cover is becoming problematic. Where the heck do I put it when it's wet?? They claim you can just shake it out and put it away to dry. It's too big to shake out myself and even with another person, it's near impossible. With snow or ice, I think it would be worse. Where do you put it when it's wet? Maybe a plastic bag in the trunk(?) or in the house. I am not too comfortable with this. Plus the car has to be clean before you put the cover on. After being driven in the rain or snow, I am not putting it back on a dirty car. It's also tough keeping dirt off the underside of the cover and you don't want that on your car either.
There are plus sides to the cover but also consider the difficulties before you make your decision. In the Summer, it's great to keep sap, bird droppings and dust off but dealing with the wet stuff is a pain!
:nixweiss
HTH. Regards, Eric