I was going to recommend the American Lawman or the Ultimate Hunter for very strong, well made , ergonomic work knives. But if you don t likee the back lock on the Endura compared to the lock on the Manix, then you might not like the excellent triad lock.
Look at the Griptilian with 154cm steel. Very strong knife. Durable. Comfortable. Don t let the plastic handles put you off. Very strong, very light weight.
And of all the knives mentioned, probably the most comfortable in hand for a heavy duty work knife.
Because I m comfortable with the triad lock, I currently use the Cold Steel Recon1, Ultimate Hunter, and American Lawman for my outdoor work. So far, very durable.