I ordered this one off of eBay a couple months ago for my 2011 GT
Ford Mustang 5 Layer Car Cover Fitted Outdoor Water Proof Rain Sun Dust 5th Gen | eBay
For the price, I thought it was a good deal. My car is garaged nightly, but has to sit outside during the day. So it gets covered daily.
I compared just about everything I could find on the web. Nothing was close to this price for what it offered. I'm sure the $300 dollar covers are better, but not $250 dollars better.
If this cover last a year through the winter it will have been worth the price.