I have all the knives you listed. The Southard has a thick stock hollow ground blade. It doesn't flip as good as the ZT 561. The Lionsteel is a great user knife, and the fit and finish are of high caliber. I love my SR-1, but I prefer a flipper in general for a knife. I also dislike the metal texturing on the lock side of the 561, the Southard single G-10 scale annoys me. The Southard also has a muted sound to it when it flips open. All in all, I prefer the Lionsteel even though it isn't a flipper, If you could get a ti-scale for the Southard that would kick it to another level for me. Don't discount the Lionsteel if your aren't set on a flipper. The Boker is made OK, but I just don't care for it, and my example has a bit of side to side play, which makes me dislike a knife very quickly.