I tried several covers, including two of the above mentioned and are indeed high quality as mentioned - though, when the California Cover folks wanted to charge you a modest additional cost for the privilege of buying one without their over-sized logo splashed on it (distracting) they didn't make the final cut. There are also some really crappy covers with brand names. I did my homework and found out that some will potentialy scratch your paint with their cellulose-based fabric material. I'm all for `going green'. But, cellulose comes from plant fiber - which comes from fields where abbrasive dirt is obviously present. There is no way to eliminate 100% of sand/clay, etc. during the harvest. This is one reason why you’ll slightly scratch your eye glass lenses using paper products to clean them. Finally, the majority of car covers are designed to fit multiple models. One, that I returned from a name-brand company uses the same application for the C3 through C6. And, they became indignant when I politely challenged them on their `one size fits all' application - because the fit was awful! IMHO many covers fall short in one or more major categories (material quality, cost, fit and often cheap chinese construction).
I bought and really like the "Sunforger" cover sold by Paragon. I noticed two C3's with them a couple of years ago where I store my C3 for the winter. I actually, discretely peeked under their "covers" to find their brand tag. The cover’s inside layer is a thick, very soft, saddle-colored flannel. The outside is a soft, tan canvas that is tailored to follow the complex curves of the C3. It looks stunning on the car. It is also water-repellent/treated if ever your garage door is opened in the rain, and is securely held on with a continuous, hidden elastic bungee cord in a sewn pocket that surrounds the cover (most have a comparatively lighter weight elastic cord or, include loops to use with your own bungee cords.) The quality bungee snugly hugs the bottom of the C3 - covering 2/3 of the wheels - soas not to rub/scratch the paint in a buffeting wind if your garage door is left open. It has the heavy duty security loops, as well, in case someone wanted to lock it, but not necessary if used indooors. I was formerly the Accessories Mgr. for an OEM and would have gladly licensed the supplier as an official Mustang accessory because of its very high quality. And, it is washable because they do get dusty sitting in a garage. They come with or without an antenna sleeve. It folds up and can be stored in a large pillow case, though I bought their optional bag.
The Sunforger company began decades ago as a American, boat cover maker according to their website.
Bottom line, havng the soft flannel on my (new) paint, the protection in my garage from minor bumps, and the way it makes the car's beautiful lines pop even when sitting under its cover sells me on it.
Dave V.