One of my partners got one and in my opinion, not so great...
The arms are cut as if they are twisted or in, they have a weird seam placement, the off the shelf ones have typical arms too small for the chest plate, therefore you go with a size to big to get your arms in and the chest plate is too wide. The material is, IMO, not much different then the Metal Viking or the Rage X stuff, just a different cut.
We had better luck with the F6 and cranking the sleeves inwards. Don't know if this guy is just hard to get shirts to fit but he doesn't seem to be, he has a big chest and moderately big arms for a 165 pounder...
I would give the Katana and the Metal X-type a thumbs down, I have the Metal and am ready to split the seams out and only have brought to my chest half a dozen times.
BTW, I just had it on him tonight, the Katana, I might convince him to keep it so I can steal it, a 220 lber getting in a 165 lber's shirt.... bring the pain, the broken blood vessels and the whole bit.