Regardless of what cover you decide to go with, use your best judgement as to how dirty your car is when you cover it. Try to give it a QD before covering it to avoid scratches or harming the finish from the abrasive dust that settles on the paint. Obviously if its very dirty do not use the cover!....
Be sure to follow Mfg. recomendations and wash or launder often.
Dave @ Innovative Detailing