I have used a Protect A Tow skirt between my motorhome and toad for several years. At that time, folks online were saying that the grass skirts tended to kick up rocks, and that the hard mud flaps either didn't ride low enough to protect or dragged.
The theory here is that those little rocks are kept below the toad. It is easy to put on and off, and now costs just under $250 with shipping.
Here's the link and a photo from their website: Protect-a-Tow