I'm sure the 520 is a great knife, and I'm still kind of tempted by the M-4 variant, the trouble for me is that I like the design of a lot of other knives a lot more. The 741 and 860, those are more my style (long blade, filling handle, flat spine/long thumb ramp, the 741 is beautifully flat ground with a hole opener, the 860 has a long sweeping blade and the thumb studs keep out of the way, and it has a low riding clip).