The serrated blades have sharp teeth that line the cutting surface. This creates a sawlike motion in cutting meat. When cutting thicker or leaner meats, serrated blades can be preferred. Also, serrated blades work better when cutting bread or certain types of vegetables. The non-serrated or thinner blades will produce a much finer cut that their serrated counterparts. Smooth blades are preferred when cutting thin pieces of fatty meats like salami and prosciutto. Each is useful and each one has their place. This is why most meat slicer enthusiasts choose to purchase one or both, and can change between the two when necessary.