Every liner lock has the same geometry issue - the ramped tang/lock interface that ensures a play-free, wear-friendly mechanism also guarantees that any force applied to the spine while the blade is locked open will have a lateral component at the lock face. Good designs and manufacturing processes minimize this problem, but can't eliminate it. Thickness of the bar doesn't solve this problem - it may alleviate it by increasing the force necessary to disengage the lock by adding material at the fold, and by increasing friction forces at the tang-lock interface. This contributes, however, to a certain inconvenience in normal use, leading to such things as "penciling" the tang lockface, which defeats the security afforded by the extra friction.
Also, even on really good knives, the locking liner often doesn't mate perfectly with the tang. Usually, it's just the leading edge of the liner face that actually engages the tang - you see this on some custom knives, too. It's a lot of effort to file the lock face to engage the tang perfectly. Even when you do, it's all moot as soon as the liner begins to wear, and the geometry changes. So even with really thick liners, you may not be much better off than with thinner liners. My old Benchmade Pinnacle framelock failed the spine whack test miserably. That was a disappointment, but also a very good lesson.
The design of the Axis lock maintains a more perpendicular interface between the locking bar and tang. Also, no matter how the mechanism wears, the tang ramp/locking bar interface always maintains it's original interface geometry. As for cleaning, yeah, junk gets in there. But I've never managed to gunk up an axis lock badly enough for it to fail to engage. But I do wish those springs were thicker.
(Back to the topic)
I'd go with the Benchmade
(Sorry 'bout the long post)
The thing to keep in mind is that the tanto tip is not sharpened so IMO the spearpoint is probably a better choice for most applications.
