I have the Nimravus also.
I have a ton of production and custom knives, and always turn to the Nimravus as a all around/med. hard use knife.
Mine is the 154cm version and will take a very, very keen edge, and hold it!
One of the sharpest knives I own.
With a 4.5" blade, it would also make a decent defensive knife.
You cannot go wrong here, highly recommended!
There is also a M2 steel version of this knife, that I have read nothing but praise about.
It should be able to hold an edge even longer than mine (which is a very long time).
Nimravus would be my recommendation.