I had the original metal, which tended to become sharp upon hitting each other.
Then the sharp edges could cut your skin.
The silicon were better, and these are a bit better yet.
I was hesitant to try the covered magnets. But these blew me away! The cover makes it easier to handle and more durable with the same strength. I am glad I upgraded.
FINALLY! The upgrade is well worth it. I just wish they did this sooner.