Both are simple to use and require no electricity. The potato ricer resembles an oversized garlic press and gives a fluffy, uniform texture to cooked potatoes that cannot be achieved by any other means. For a long time, about the only place to find such an apparatus was a flea market or thrift shop, where battered old ricers, their lead paint peeling off in big chips, rattled around in large bins among other forgotten utensils. Most people didn't know what to do with them. Today, you can find them in better cookware and hardware stores.
Most food mills have hooks that allow the machine to rest on a bowl or pot.
The best food mills are made in France, have two or three plates with different sized holes, come apart for easy cleaning and are simple to reassemble. The most important action of a food mill is that it purees a thing without incorporating air. If you have ever had a sauce that was unpleasantly foamy, you will understand exactly what I mean here. A blender or food processor traps air as it grinds, purees, and emulsifies. It is ideal when making tomato sauces, soups, and fruit purees.