It allows a citrus zester by not imposing the outer part of the skin (the one that contains essential oils that research), not the white, bitter skin. As she very fine grater, it is ideal for lends a pep plate just before serving.
As perfect for hard ingredients: Parmesan, hazelnut, nutmeg, tonka bean, etc.
I also use it often to reduce garlic mashed: very fast, and a pulp is obtained which easily dissolve in any dish or sauce.
So why only three stars?
Simply because this model (which kept the shape of the wood rasps, the original function of this tool before it is adopted by cooks) is not the most practical of the range. I also have the "professional" version of the toothing is identical but whose shape is more like a conventional grater, or a small mandolin (wide blade and shorter); and of the use I find the model "pro" more convenient. The width of the strip simplifies the work in many cases, and the recovery of peels or garlic pulp is much easier.
I recommend instead the "pro" form (search "Microplane steel sleeve"), even if it is 20% more expensive, or form "gourmet" (identical to the "pro", but with a plastic handle, such as this collection).