Check the fill hoses and fittings to make sure they are rust resistant and strong enough to last under high water pressure. Most washer models have a porcelain-coated wash tub, but you'll want to find out if the coating is thick enough to withstand years of use without chipping. Stainless steel and plastic tubs won't rust, but check the surface to see if it's smooth enough to protect fine fabrics. If you're going to use the top of your new washer as a work area, a porcelain enamel surface is more durable than paint. And, be sure to check the warranty.
Some manufacturers cover rust and corrosion.
If your washer will be placed near a living area, you might want to spend more time thinking about its appearance than if it will be in the basement. Choose a style and color that blends with the rest of your home furnishings.