Like many who've already posted to this thread, I too enjoy Nutnfancy's reviews for their thoroughness and detail. He is singlehandedly responsible for my addiction to knives.
But after buying my first knife -- the Ontario Rat-1, an excellent blade -- based on his and other reviews, here are some very important things I learned:
1 - What might look like a small-to-medium-size knife in Nutnfancy's hand is actually a medium-to-large-sized knife to those of us with average-sized hands (to say nothing of folks with smaller hands). He often says in his videos that his hands are on the large side, but you don't realize the scale until you can actually hold some of the blades he reviews in your own hand. The Ontario Rat 1 is HUGE to me. Too big, in fact, to be practical for me. I will be looking to unload it. It's a great knife, though.
2 - Nutnfancy espouses knives as last-ditch defensive weapons -- and for LEO and military personnel, I can't argue with that. All I know is that, not being LEO or military, I will NOT use a knife as a last-ditch defensive weapon. Without getting into personal philosophies here, just keep the heavily-focused "tactical" angle of his vids in mind when considering his advice. For example, do you really care about "reach in a defensive encounter" when considering blade size and length? I thought I did, and therefore was looking for the lightest possible folder with a 4-inch blade. But after holding a Rat 1 with its 3.6-inch blade and imagining the damage it can do to human flesh, I know that there's absolutely no way I'll be wielding it with the intent to cut or stab another human being. Therefore, I've decided that even 3.5 inches is too big for an urban dweller like me; yet many of the EDC knives he recommends are 3.5 inches and up. He does recommend smaller knives, too -- such as the Flash 1. But the Harsey model you're talking about is absolutely gigantic. Of course, this all gets into my own personal tastes, and others might find 3.5-inch knives puny.
3 - With regard to fixed blades, I've found through watching other reviewers on YouTube that "larger isn't always better." While Nutnfancy readily admits that, under certain circumstances, larger knives can be an impediment, he by and large favors 7-inches in length and up for serious outdoor duty. Getting back to my own tastes after holding a real knife in hand -- as opposed to just watching YouTube vids -- I feel that for me personally, 5 inches is the upper limit for me, based on the fact that even the Rat 1 folder, at 5 ounces, seemed like it would significantly add to the overall gear weight of whatever I was packing. Rather than the large blade, I am going to try a folding saw or pocket chainsaw for the big cutting duties.
Notice I said, "going to." This brings me to my closing CAVEAT: I don't have one iota of experience in using knives outdoors and Nutnfancy has years. So take what I say as simply another "data point," which is an expression I borrowed from Nutnfancy himself. I am new to knives and have Nutnfancy to thank for that (or curse -- seeing as how much time this new hobby consumes).
BOTTOM LINE: I love his vids and hope he never stops making them.