I don't buy it. In the kitchen, less is often more. These things are simple, easy to use and easy to clean. The few times I have given in to the allure of expensive specialty gadgets, I've regretted it. If I were cooking for 20, it might be worth learning to use it.
Many people swear by it.
For years I've pureed soups in my old Krups blender, despite cookbook warnings that the texture will be wrong, soups will be starchy or other horrible outcomes. I stuck the food mill in the back of a cupboard and went back to my trusty blender. If new gadgets often disappoint me, some of my oldest tools delight me. I just couldn't bring myself to buy a new plastic juicer or a sifter that didn't have a handle to turn. And I cherish the big wooden spoons from my mother's kitchen, still stirring strong.