I'm assuming you own both, which do you prefer? how are the ergonomics on each?
I used to own both XM-18 and Yuna mini hard 2. Yuna is still with me, but I have sold XM-18 not long time ago. Both are big and heavy knives. Both are tough knives.
With blades that are 4mm thick they are great for the hard use. Yuna's laminated ZDP-189, hollow grind and great blade geometry is probably a better cutter ("probably" here, because I never had to cut stuff for 3 hours straight, and if I had a job like this, I would use something other than either of those knives). Yuna has strong tip, but XM-18 has even thicker, stronger tip, so it is better for prying.
XM-18 has more of a "general" sculpted handle, Yuna has more curves to fit the hand. I feel that my yuna was designed for a bit bigger hand than mine (I have small hands), but it still fits nicely. Same with the reverse grip.
I really like Hinderer's thumbstuds (blade stops). They are easier to use than Yuna's. Yuna's should be considered more of a blade stop. As thumbstuds they are very difficult to use for opening, kind of like studs on Strider. Flipper on the other hand on yuna is very nice. I like it a lot more than the one on Hinderer.
Blade retention on Yuna is much better. I could open Hinderer's blade simply by shaking it a bit. Yuna's stay closed even if I try really hard to open it using gravity alone. I prefer Yuna's way, it is safer, and it presents less problems with ignorant people in uniform.
Hinderer's lock is thicker, Yuna's is like on a Stider. You can actually ask Yun to put a thicker titanium, if you desire.
With Hinderer you have a choice of standard scale colors. With Yuna, there is a bigger selection. You can have one or two tone G10 over titanium, you can have bolster area with a different color, you can have both sides as a solid titanium piece. I like the heat coloring on yuna's handle.
I love Hinderer's pocket clip. Not too high, not too low, up or down carry, looks good too. Yuna's clip is nice, not too high or too low, but you can't reverse it (I like tip down carry).
I have chosen Yuna over XM, because I liked the looks, I liked the feel of it. It suits my needs and uses better. And I like the way yuna is made. Something about being homemade all the way, using just very simple tools, makes this one special. I probably will pick up XM-18 again when the rush is over, but not as a replacement for yuna, but rather as an addition to the collection.
In the end it really comes down to individual likes and dislikes. Choose what is better for you.
