Dragon I concur with Gus for most trainer/sport models nylon clevis' are fine. There are poor quality ones of both types. Additionally Metal Clevis' have just as many failure modes as the nylon types, just differant. One of which is some brands of metal clevis are effected by vibration and the threads can eventually strip (not good). Some are stramped and rolled with a seam running the length of the threads. This seam can expand allowing the clevis to start sliding on the threads too.

One major warning though: Never use a metal clevis on a metal throttle arm. If it is a metal arm use a plastic clevis. Vibration at this point can and will cause radio glitching problems (not good).

Some of my favorites are plastic with metal pins (of course not on a metal throttle though).

John