There are many metals to work with but steel, stainless steel and aluminum are pretty common. Metal is an excellent material to use. From an exterior stand point, powder coated rails may last 10 to 15 years maintenance free. Wood on the other hand rarely lasts that long without needing new paint or rotting away. Stainless and aluminum have other great qualities. They don’t rust or even necessarily need to be coated if that is the look you desire. I also offer custom CNC cut parts.
Picking the right hardware might make you nuts but in most cases it is simple to pick hardware that fits or accents the look you are going for.
There is a multitude of hardware for cable rails and the price sometimes varies a lot and also effects the price of the rails per ft.