I have used 105 resin with the slow and fast hardeners for many years. The pumps work well but dispense too much in one push for most knife making applications. I use a little scale to weigh it out. The epoxy is pretty thin, I use it mostly for laminations, but have glued up all my knives with it. The fast hardener will turn reddish brown over time, I think this may be worse if you keep it in warmer temperatures. The slow hardener stays clear a lot longer, but will also darken. I now keep it inside and it does not seem to darken as quickly, but I still would not recommend it if clarity is important to you and you cannot use it up in a couple of months or so. I believe they have an extra clear hardener, but I have not used it. If you are used to five minute epoxies, this stuff will seem like water. I frequently use colloidal silica and other fillers for thickening. Even with the fast hardener, this stuff takes long to cure and I always leave it to cure overnight. Lastly, this epoxy produces an oily film that is called "amine blush" during curing. That will probably not matter for most knife building with the possible exception of bedding tangs, where the amine blush could prevent a good bond when you glue the blade in permanently. I wash out the tang hole with alcohol a couple of times and so far so good.
Long story short, I use it for making knives because I have it around anyway and I am familiar with it. If I had to buy epoxy just for knife making, I would probably get something else.