I have been using the SkyBrush xE for five months on our whiteboards. I used to think that all board erasers were the same, but not anymore. The SkyBrush xE is hands down the best whiteboard eraser I have ever used. With one simple light swipe the board is clean. No longer do we have to use additional chemicals to clean the board.
[Note: Owners of cheaper whiteboards may want to be careful as the glass bristles used in the Skybrush can wear away the surface over time.--OH]