Ok I am going to be rude and say that almost all seat covers are nasty. I dont see the point of them. I mean why bother choosing an interior colour or a spec that includes a nice upholstery if you are going to hide it under some other fabric all its life, just to 'preserve it' for the next owner. Its like covering a leather lounge suite with clear plastic, or putting a plastic runner on top of new wool carpets at home.
One exception would be the really nice waterproof jobs you can get for landrovers, emblems and all, which I would put on just for a safari trip and them remove again for daily driving
That said I also used to think that those fluffy sheeps wool covers on a mercedes in the late 80's, early 90's were the sh1t, and everybody had them! : )