My vote for most underrated (as first post inquired) is the Buxton.

For all the folk looking for a general purpose outdoors large knife, but still quite portable, it is the naz. Personally think if it were cataloged, it would have swiftly become the #1 seller among troops back when the conflicts in the East ramped up. Very amicable to latest gear needing a compact heavy duty knife with good deep shearing.

As it is mostly a complete unknown to the public, but which could have skyrocketed to #1 modern military most demanded knife with better press, that fairly meets my idea of underrated.