I've probably killed more animals with the Delta's than all other heads combined. I used both the two and four blade, but am beginning to think the hassel of sharpening the two small blades isn't worth the gain. I'm still working on that though. I never have had one fail. I have nothing against the Eskimo, it actually has a stronger tip, its just the straight edge of the Delta is faster to sharpen. Don't forget every animal, up to and including elephants have been killed with Zwickeys, not many heads can say that.