Steel patio furniture has gotten a bad rap over the years, mainly because the furniture from the past that is susceptible to corrosion, eventually changing the expensive set into a pile of dust.
But today steel patio furniture is more resistant to corrosion, thanks to new production techniques, better primer and paint and maintenance and improved treatment methods. With proper care steel patio furniture should last as long, if not longer, than furniture made of wood or aluminum. Possible rusty steel furniture in the first place depends on where you live. In warm, dry climate, corrosion is almost non-existent. In the northeast, if left alone, the steel rust more easily.
The advantage of steel patio furniture is much greater than the disadvantages. Steel is much stronger than aluminum and steel frames can make finer and finer, due to higher tensile strength. Of course, rust is a major drawback, or at least has been in the past generation. New upholstery really changed all that. High quality steel patio furniture is coated with a dense layer of primer and paint, keeping the rust problem to a minimum while protecting the steel from the elements and even damage from accidentally scratches and scrapes of everyday use.