With two little girls running around the house I couldn't think of not having a magic eraser around the house. I have truly fallen in love with this product. My daughters bang and clang all their toys and they always seem to hit the walls. I no longer have scuff marks on my walls.
The magic eraser works wonders. It is very simple to use, you just get it wet and rub the area. Magically, it's gone! I know you can use it more than just on walls, but that is all I have ever used it for. Another great thing about the Magic Eraser is that they are very inexpensive. They are about $3 for a pack of two.
I do know that if you rub to hard on wall surfaces you could rub off the paint. But, if you are careful and do not rub too hard this will not happen to you. I highly recommend Magic Erasers for anyone who has scuffs on their walls Even works on crayon marks!