I've used the BK-9 extensively and in my opinion, ignoring the heat curved blade, non-spine centered edge and other major cosmetic blemishes, it is also not enough knife for "survival chopping" because the 3/16" stock is wrong for that purpose.
Being tired and spent out is a major consideration for survival use, even if the weight of the knife might contribute to some of it... Anyone advocating smaller knives for shelter building either doesn't realize the extent of the work needed, or they have not spent a rainy night in the "easy" builds... Also longer edges are better because they grow dull slower: Simple fact.
That being said, the BK-9 is not a terrible choice to that end, if on a budget. The Ontario SP-52 and 53 are way, way better, and are even cheaper, so I don't quite get why the BK-9 gets so much attention in that corner of the price range...
Despite being broad bladed, fat handled (which is essential for a real chopper, and where the Trailmaster radically fails) and quite long-bladed, the BK-9, due to its thin 3/16" stock, does not chop much better than a Cold Steel Trailmaster or a Chris Reeve Jereboam, which are also sub-optimal knives for chopping, and most other fine tasks (edges too thick, at minimum 0.040" on the CR, and worse on convex Trailmasters).
I would think the Esee Junglas or Ontario R-Tac 2 are similarly compromised by their thinner 3/16" stock, depending on how thin their edges are. Despite the compromise on blade stock thickness, they are still quite heavy at around 20 ounces, because of the misguided full exposed tang designs which wastes a huge amount of weight in the wrong place...
I think 0.22" to 0.25" stock is really the ideal range a good chopper blade should be at, if the weight issue is mitigated by a stick tang or hollow handle.
Any Carbon steel is a big downgrade in edge durability under hard use, especially in survival conditions: Any rain on the edge, while the edge sits in a sheath, and within hours a lot of fine-cutting versatility will be lost through the edge rusting. Stainless crushes any Carbon in hard-use edge-holding anyway, so the current emphasis on Carbon steels is truly bizarre...
The best stainless chopper for the weight and size is probably a Randall Model 12, with its versatile 0.020" edge: Due to the thin edge and hollow grind (which round handles can't use because hollow grinds tend to roll in wood, and so round handles are limited to flat grinds), the Randall Model 12 outperforms the Bk-9 by a ratio of around 2:1... By contrast, the Ontario SP-52-53s out-perform everything, but these have thick edges that are not versatile for fine tasks. They are, additionally, in Carbon...
Closest stainless competitor to the Randall 12 would be a Fallkniven Thor, which is almost as expensive. I had to re-shape the handle of my Model 12 for optimum performance, so maybe the Thor out of the box is closer, but the Thor's handle is much too thin, scary slippery, and transfers force poorly (being similar to the Trailmaster)... The stick tang is definitely a big plus, but the Model 12 also has one.
All the Busse knives are very thick behind the edge, a few odd thinner ones being at least 0.035"... But 0.050" to 0.060" is far more typical for Busse, which eliminates them from serious consideration: At 0.060" and over you are basically bludgeoning your way through the wood: It takes a lot of time and is painful to watch... The lack of stick tangs also means the weight is horrendous for any given stock thickness...
Gaston