The problems that plague most liner locks are due to security issues, they are in fact very strong, assuming a sensible liner thickness, which you will find on any decent quality blade, Spyderco Military for example. Many people think the newer locks have the main advantage of strength - but a simple lockback can easily take a few hundred pounds if applied straight down.
The first problem with liner locks is that you are unlock them with torques. As you twist on the blade the tang can exert a shear force on the liner and cause it to move backwards. If you twist hard enough you can move the liner right off the tang and disengage the lock. You can do the same thing with Integral locks.
The second common problem with liner locks is that you can white knuckle close them. Again there is a shear force on the liner which causes it to disengage. You can get away from this problem by really deep seating the liner far down in the handle. Integrals depending on which side the lock is on, can either be unlocked in a tight grip or jammed tight, turning it into a fixed blade. As well because they are actually one side of the handle you can not deep seat them to remove the disengaging problem.
Note with both of these cases, it is not necessary to completely disengage the lock, if you move it far enough so that the entire liner does not engage the tang you have greatly reduced the durability of the lock. If you apply a load with only partial engagement you can snap off a piece of the liner. How much force it takes is dependent on how much of the liner is engaging the tang - which is dependent on how much torquing or compressive force you are exerting in either case.
The wear issue is also very critical as the part of the lock that wears is a very large part of the folder on Integrals. The Integral lock is possibly the worst lock in this regard as if the locks wears excessively then you have to replace one whole side of the handle. And what is again worse is how these locks fit into place (liners and Integrals), the two mating surfaces actually have to grate over each other in order for the lock to engage. Compare this with the action of a simple lockback.
In regards to the security and ergonomic issues, the lock on the Integrals actually forms the handle and when it engages one side of the handle actually caves in and thus the handle slabs are not in-line. This is very low in terms of ergonomics and comfort as opposide to a fixed place handle slab.
The replacement cost/difficulty is also an issue. Look at other locks and see how they would be repaired if the tang wore too much on the part that engaged it. The Integral lock has one of the most difficult to replace parts, and one of the highest wearing ones for reasons described in the above.
Numerous threads exists on the problems with Integrals I mentioned, if more detail is desired.
Now in general are Integrals more robust than liner locks? Well yes - but consider a couple of things. Because in general liner locks are on *much* cheaper blades they are of low quality in terms not of base design but of implementation and QC. As well the user base for low end knives is going to have a much higher frequency of heavy use than knives that are 10x the cost, this will skew any comparision based on number of reported problems for example.
As with anything, not everyone has the same needs in a knife. Would a Busse Combat Integral folder be well recieved, yes I would think so. Integral locks work very well for some, as do simple liner locks which are extremely popular. Les Roberston for example sells many liner lock high end custom folders and does not see folders failing the spine whack test (which can unlock many liner locks) as a problem because he sees such usage as abusive. My point is simply that it is not a lock (liner nor Integral) I would want to see on the Busse Combat folder.
-Cliff
[This message has been edited by Cliff Stamp (edited 05-09-2001).]