I use gerber knives and a multitool. and keep them sharp, but not so sharp that you can shave with them. A super sharp knife will dull and it's hard to maintain that edge in the field unless you keep a stone of some kind with you. I wouldn't waste a sharp edge on a rock. It will dull fast enough with normal use. I sharpen my blades with a Smith diamond sharpener on the course side only. To test the edge I drag it across my thumb nail. If I feel a consistant drag I know it's sharp enough. It will cut paper with ease. To get cut with a dull knife is bad and the cut more painfull. The cut of a sharp knife will usually be deeper but will create less scaring. I got a finger cought in a bandsaw mishap and it turned a small area into what looked like hamburger meat and would have been hard to stitch. In closing, use a sharp knife to get the job done easier and be aware of what you are doing with it.
Never stab fruit while holding it the palm of your hand. <img src="/forums/images/graemlins/grin.gif" alt="" />