I had one of these and it's a seriously cool gun. Unamped it's got the same eco as an adj hero +a204 but with over 7dam/sec more, and the only thing that stops your hunts is the inability to carry enough ammo
Add an a204 to it and you've got a cool killing machine with eco that beats just about anything but an imk2.
The range means your armour/fap decay is very low, and many mobs can be hunted with no armour 'cause they drop at your feet. When I first got it the raw eco figures showed I should do better with a korss, but the range and dam/sec makes a big difference and my hunts with mkVme were always much better than when I used korss.
WARNING: there is one huge drawback with this gun, it'll make you want the imk2 even more once you get a taste for one of the few truely great guns in the game.