I would go with the RTAK.
WHY?
SOG uses 420 stainless for the knife you mentioned. I would never buy a knife in that steel, except possibly in a beater folder and I mean BEATER. 420 is very hard to sharpen and I am really good at sharpening. ALso 420 is a brittle steel because of is high chromium content which is the stuff that makes steel, stainless. So, as a beater, it might not have the life span you hope for.
The RTAK uses 1095 steel which is a carbon steel. That means it is very easy to sharpen which is what you want in a large knife. Also the high carbon content makes it a flexible steel which will not snap on you. Plus, Jeff Randall designed this line for Ontario. He conducts survival training in many differemt regions on the world especially jungles. He has been testing and using knives in extreme places for many years. I would trust his choice more than many others.
Big knives are for hard use and 1095 is a stronger steel than 420. If you lay out money for a big knife, you will want to depend on it, so you should buy a knife that you can depend on.