The DMT diamond sharpener you showed above is one of my favorites for sharpening knives in the field. As long as you can keep the angle you can put a razor sharp edge on most knives. I do however recommend you practice a lot on cheap knives before you work on expensive knives. Sharpening is an aquired skill that can serve you well in the field. I would get the DMT and practice with it, the Spyderco sharpmaker is great, but you can do a fine job with the much smaller DMT.