Flip a coin (a three sided coin

). They are all nice knives. I have owned or currently own all three of them. All of them cut stuff. They are all tough, well made, well supported by their manufacturers, and well thought of on this forum. All of them will last you a lifetime or two with a modicum of care.
The RC-4 has a great sheath system that is extremely versatile. I like mine because I can go from a belt loop, to MOLLE, to a Tek-Lok with the same sheath. RAT really builds a lot of functionality into their sheaths. The high flat grind on the RC-4 really cuts well for such a thick blade.
The BRKT Highland is typical BRKT - meaning it is great. A2 is a great steel that takes a very fine edge easily and holds it. It is compact in size but still more than enough knife for most tasks. The Highland is kind of a classic.
The F1 is great too. They have some nice sheath options (I love the two kydex sheaths I have from On Scene Tactical, the OEM leather flap sheath is excellent, and JRE makes several great sheaths for these too). The ergos are quite good. VG10 steel is one of the only stainless steels that I like because it sharpens more like a carbon steel. The F1 is just a great all around knife.
So, like I said, flip a three sided coin if you can find one. Otherwise you will just have to get all three.
