I don't see a reason to choose the more expensive cover. You could always buy the cheaper one and use $15 in 3M ScotchGard and likely get the same result. Careful with the cover though: you have something sitting directly next to your clear coat, so any dirt or even light dust will be trapped against the surface; any rubbing will result in micro-marring / swirls. Make sure it's only used when the car is super clean as it's hard to clean a giant car cover.
Gotchya; thanks!