Mandoline slicers are useful for getting perfectly even cuts, especially when you're trying to make them extra thin. Sure, a sharp knife will do the trick, but mandolines guarantee perfection and uniformity. They can be used for everything from potatoes for scalloped potato dishes to eggplant for parmesan or grilling. Here are the best mandoline slicers you can buy, according to testing, home use, and brands we've used before and trust.