not really. unless you have brand new skis or sharpened edges. Usually a couple runs with a file at 45 degrees preps them though.
Cons to metal rails are they require maintanence to slide well. they must be painted and waxed, or they will rust, or just get sticky. PVC just slides.
Steel is nice though for stopping after a spin on. much more grip there to slow your rotation.
I prefer PVC for slow speed flat rails on slow summer setups, because you can carry your speed across them much easier, and you don't need as much initial speed to hit it.
I prefer steel for steep downrails or kinks, because the added friction makes them easier to balance on at high speeds, and dropping from a considerable height onto them is much less sketchy. big drops to pvc shatter the pipe, that is if you don't slip out.
One last thing to consider if you plan on lapping this rail constantly: pvc doesn't cause edge wear...