I'm slowly gathering accessories for my table saw. Most of the sled plans I've seen have wooden rails to slide in the table grooves. But I've also seen some metal rails and I wonder if they wouldn't be more precise. They aren't cheap so I wouldn't get a bunch, just a pair to move from jig to jig. Is this a reasonable acquisition? Or should I just cut wooden rails?

I'm slowly gathering accessories for my table saw. Most of the sled plans I've seen have wooden rails to slide in the table grooves. But I've also seen some metal rails and I wonder if they wouldn't be more precise. They aren't cheap so I wouldn't get a bunch, just a pair to move from jig to jig.

Given the different materials what would make me choose one over the other? What would I need to consider when choosing my rail material for my sled(s)?