I took a bunch of photos months ago when I received my UFK/FK2 to compare it to the original FK. I never got around to posting them or adding my thoughts, so here goes in no particular order.
The UFK has a taller blade grind, larger sharpening choil, more belly than the original FK.
Handles measurements are difficult to compare sometimes given all the subtle angles, curves, and profile characteristics.
The top portion of the handle on the UFK is slightly longer than the FK.
The shape of the bottom side of the handle and position of the palmswell on the original FK are a couple of the features I most appreciate about that knife. This area of the knife remains essentially unchanged on the UFK.
I prefer the forward tapered thumb ramps on the UFK over the outward flared end on the front end of the handle on the original FK. I like this feature because it makes the transition to a pinch grip comfortable and easy.
The handle on the UFK has more of a flare on the back end and a wider palm swell than the original FK. I think the more Rubenesque curves on the UFK will appeal to more folks.
The UFK eliminates the pry-bar feature from the original FK.
The balance point on the UFK is approximately 3/8” behind the center of the front screw.
The original FK shares a similar balance point (with micarta scales), yet the “distribution” of weight is better with the UFK than the original FK. The UFK feels more lively in hand to me.
A small piece of trivia is that both the TeroTuf and Burlap micarta UFK handle scales weigh exactly the same.
The one area where the UFK paled in comparison to the original FK was the blade finish on the primary grind. The as machined tool marks were obvious enough to awaken OCD feelings I never had before when compared to every other CPK I own. I understand the intent to keep cost down by eliminating a secondary grinding step, but I am glad that Nathan has heard the feedback and added it back in on future knives to maintain the look we have come to appreciate from CPK.
I ultimately sold off my UFK in favor of the FK mainly because of the blade finish. This FK holds a special place in my collection because it was a very thoughtful gift from a dear friend.
The original FK hasn’t lost a beat performance-wise to its newer sexier replacement. I think most buyers will prefer the ergos of the UFK over the FK if all other factors are equal. Either one will serve you very well for a lifetime of use.
Phil