The Mustangs are the only way to go, slip them on & off easily. Unless you want to see your paint, then the clear plastic ones that snap on. Not sure on their name though.
I have the same lid covers on my bike. Love them! Used to scratch the top when I swung my boots over the bike. Now, a little leather cleaner, and I'm rolling on.
From past experience on cars, I suggest if you put them on you put two or three coats of good wax on before installing and clean under and/or reapply wax in regular intervals. This should be enough to protect the paint under the lids.