The biggest pbelrom I've run into with the Chef's Choice sharpeners is that the magnetic guides do not work well for small knives like paring knives.Now, as to professionals only using hand stones, that is balderdash. While many people do use hones, steels and strops, many pros rely on a motorized grindstone for results. While you do need to be careful using powered sharpeners it is also very easy to ruin an edge with a hand stone since it takes experience to keep the edge at a consistent angle.