Nah, I've actually had way more trouble with the metal ones cracking under pressure. Sorry sean_walker45, but that plastic gear can take a beating lol.
You know, I have to side with leo_murphy on this one. The metal head is usually the weak point, not the plastic gear. That snap on a Berber is almost always from the head itself getting bound up, not the gear stripping. Seen it happen a dozen times.