In all actuality, it depends on what you're trying to clean off in the first place. Vinegar and water will remove most mineral deposits, but won't have much of an effect on general dirt and the like. If you want to get a dirt, dusty washer really clean and sparkling, you need a non-abrasive cleanser like Bon Ami and a sponge and a lot of elbow grease. With all cleaning, the trick is to tailor your cleaning product to the material you're trying to clean and what you're trying to get rid of.
Above all else, remember that "non-abrasive" is your mantra in cleaning these things.