Most places have "banned" metal spikes for a number of reasons. Mostly because of the damage that they do to the greens.
The most visable is that they tend to spike up the greens. We all hate this because it can really add the luck factor back into our putting. Remember, no tapping down those spike marks!!!
The less obvious is that as the spike wear, the tips tend to form a small mushroom shape. This shape picks up different material (mostly grass) that is transplanted all over the course. Imagine walking through clover in the rough and then having that move into the green complex. Superindendants hate this. It is very difficult to kill all of the unwanted grass species in a green without spending a lot of time and money. You also risk longterm damage to the green root system.
I will personally never wear metal again. The alternatives not only work very well but are better for the course.
Look at the Champion Tour players, very few if any wear metal. It is just to hard on your feet.