I've used mine quite a bit and love the design and the steel. I decided to start applying more down pressure (easily 50+ lbs, probably 100 at times) and I've increased the lateral pressures to something that feels unwise (not to 100 lbs, but enough to break some of my old knives).
Awesome steel... simply awesome.
It locks in place freaky good when heavy down force is used. Disengaging the lock isn't easy, but at least the blade is most definitely in a solidly locked state.
I also decided to let the M4 get dull to see what it takes to bring it back.
That was a mistake. It may seem easy to keep an edge on, but if it goes dull it's a mofo to bring back (I'm using extra coarse for reprofiling with the DMT aligner).
Kind of a pain to reassemble, but it all interlocks into a piece that is solid and functional for a hard folder use.
The blade will rust fast in the right conditions, but cleans up well.
Damn good knife.