I got this disc hoping it would become my new putting putter after I cannot find a westside bt soft swan 1 reborn anywhere and while I am somewhat successful with it I can't see myself using it much longer. It is a little too domey for a putting putter but it does throw really well. Flies almost identical to a kc aviar 

I have this disc in Ground and Armor plastics. 

I bought these discs trying to decide if I liked non-beaded putters. Turns out I do when putting from a distance outside of Circle 1. Huge fan of the Viking Disc putters and the Knife is a great option with a predictable fade at the end. 

I  got the Armor plastic to throw, and the Ground plastic to putt with. Armor seems to be indestructible and shoots out of the hand. Ground is nice and grippy and holds onto the chains. 

Absolutely love the Knife. The Armor plastic has a great feel and it's durable. The Knife is as reliable from 200ft out as it is 30ft out. Ever so slightly understable 
 

This review is for the Knife in Armor. I provide another review for the Knife in Ground Plastic. I have two of these stable putt & approach beadless discs, one in Armor (173 grams) and the other in Ground Plastic (170 grams). The rim to each of these discs are the same, but the top plate are different enough resulting in different flight patterns; the Armor is dome top and the Ground Plastic is flat top. I use the Armor Knife for backhand long approach shots (up to 200 feet) and use the Ground Plastic for forehand short approach shots (50-70 feet).

I think the dome top Armor version of the Knife has a different set of flight numbers than what is listed for the disc. From my experience, the stock flight numbers match closely for Ground Plastic, but for Armor the putter has greater glide and more turn before a lesser final fade than the flight numbers suggest. I also think the Knife might be 3 speed, regardless Ground Plastic or Armor. The Armor is a durable plastic able to withstand some power and hits, better than Ground Plastic does. That is why I use Armor version of Knife for backhand long shots requiring more power than short forehand upshots.

If you like a domey putt & approach disc for long upshots, give the Armor version of the Knife a try.

Fantastic!!! My first putter was an aviar switched to a pig and I checked this knife out in the ground plastic and it fits in my hand very nicely with the feel of say an R-Pro which I love my pigs as well. I now have four of these, one pink and my favorites are my 3 with white with black stamp. Buy them when you find them, I feel like they are hard to find.

My experience with the knife in armor plastic is it is slightly less stable than than advertised as per usual of Viking Discs. Off the tee I saw a straight flight with a nice fading finish. The knife does feel good in my hand as I prefer flatter profile putters. I find that I can get some nice touch flicks with it as well, just have to be careful you don't put too much power in it.I have removed it from my bag as I'm experimenting with similar and more over stable putters, it may find its way back if I can't find a good replacement.