I bought just one steel beam to compare to the aluminum ones. One negative is the width is much more narrow than the aluminum, so less contact area for whatever the load is. I like the steel to be able to weld brackets or drill holes for attaching angle iron support panels. The material is thick enough to allow for welding and rivet type threaded inserts. The smooth top surface is better for carrying steel or tubing because the aluminum ones have a ribbed top that could either be damaged by steel stock, or could itself damage the surface of things like pvc pipe, though you could easily pad it. Anyway, good product!