Long lasting, and only requires a splash of water to get started sharpening to a razor thin edge.
600 grit is inbetween 800 and 400 standard grits. 800 being considered a medium coarse grit, while 400 is considered a coarse grit. With a 600 grit sharpening stone, you get the best of both worlds. A coarse enough stone to sharpen extremely dull blades, without removing too much metal.