With some practice, modern one hand openers are as fast as assisted openers, and autos, plus they have no springs to fail, or little, hard-to-find-under-stress, buttons to press.
I just shipped out a Kydex sheath I made for a NJ LEO's BHK (which he purchased and left with me at the Valley Forge Gun Show) on Monday. I don't know the model name, it's a little Wharncliffe with what looked to me like curly maple scales, about the size of the smaller one in your photos. Same...