When choosing railing systems, you want to consider cost, how easy they are to maintain and how robust they are.
Aluminum will not rust or rot. With a properly applied finish and little maintenance, you do not have to repaint it over the life of the product. Wood, on the other hand, needs to be treated or painted every few years. Inevitably, wood rots and at some point will need to be replaced. This adds to overall costs in the long run.