I have owned two from Toms. Up side is that the backing is easy on your paint. Down side is that both ended up being permeable to water, and the first one started shedding part of the backing after about a year. I ended up buying a cover from California Car Covers and they are really good. They have different types of covers for different applications. I bought a Cal Cover Storm Weave model for my 74 EB and it doesn't leak, even after two years in AZ sun. I use the newer Tom's under the Cal Cover. They actually don't recommend that due to the possibility of condensation, but here in AZ that's not a big deal. Anyway, check out Cal Car Covers. I also bought covers from them for my old P-car and new Tundra. Obviously I am a big believer in their covers.
Bob