I endorse the use of a genuine Shimano chain breaker, my two examples have effortlessly cut hundreds of chains and pressed many a special pin back in over at least 20 year's time. Never bent a pin! Even the standard-looking models that I have normally cost more than most others, and well worth it.
My Columbian bench vise was inheritance from my late grand-aunt's basement, and now serves well year after year in my basement.
Oddly though, I didn't actually pay anything for either of the chain breakers either, since Shimano would hand them out to seminar attendees when they introduced a new gruppo and chain width.
