Does iPad 2 need Hard Cover or Silicon Cover

I want to buy a protection sheet for the iPad 2. In a store, there are a hard back cover and a silicon back cover. Both are the same price. Will the silicon be better against the fingerprints and sweat of your hands? The price in no issue. Can anybody share your experience with such covers?Both covers will protect your iPad from scratches, but the silicon will not do much much to protect it from