I have a Benchmade RSK that I recently purchased and have already dulled and resharpened several times (it gets a lot of hard use <img src="/images/graemlins/smile.gif" alt="" />). It's an S30V blade (which I love) and I have had great success with a Lanskey natural stone in the fine and super-fine grades with Lanskey honing oil. Starting of course with the fine stone then finishing up with the super-fine stone. I can shave the hair off the back of my arm after about 30-60 minutes of sharpening. I imagine a very fine diamond sharpener would be even faster but I don't own one (yet) for my Lanskey kit. The only diamond sharpener I own is a tiny hand-held "field" sharpener which is nice for a quick sharp on the fly but not as effective (for me) as the lanskey with its nifty angle guides.