I have all three, and all three are different tools. Comparing them is, to me, like comparing pliers, a screwdriver and a socket wrench It truly depends on what you will be using it for. The 2 is good for bushcraft and common everyday tasks, the 7 in my mind is a fighting style knife, I feel the blade is thinner, not in thickness but blade width. I would not use mine for wood processing. The nine is a wood shark. That thing will eat a tree if you want it to. The balance and design is made to destroy timber. It all depends on what you will be using it for. If you want an all around blade, get the 2. There is no in between. The 2 can do most every task you ask of it, some easier than others. And keep in mind, a BK2 can cut through a tractor. And a refrigerator. And an airconditioner. And nails. The knife is simply amazing.