I prefer brass. The Porter Cable guides are fine, they install easily, center easily, and perform flawlessly,, Most of the time. Just once in a while though, they fail completely. Steel, no matter how you protect it, will eventually corrode. Mine turned white and rusted, not all over, but on one side or the other. My guides often get removed from the case and hauled out to the job-sites while attached to the router. Early, foggy mornings and those sudden summer-time cloud bursts, expose my tools to far more of the elements than I like. So maybe,, it's my fault. But brass just hasn't let me down yet.