I tried the Kone Pure Optical but I wound up using a Zowie EC2 eVo CL over it. The mouse fit into my hand pretty well but something about the Kone Pure Optical felt less precise than the EC2 eVo CL. I read into it a little bit and I think it may have something to do with where the sensor is positioned on the bottom of the mouse. Grip wise, the Kone Pure Optical is mediocre at best I would say. I have moderate-moist fingers and when I first picked it up, the mouse was extremely slippery in my hand. Comparatively, the coating on the EC2 eVo CL (not the regular one) is great for me. I can get a good grip on the mouse the first time I put my hand on it and the mouse maintains it's grip even as my fingers get moist.
While the EC2 eVo CL is fairly comfortable in the hand, I find it fatiguing on my hand after a few hours of use. I'm going to try the Zowie FK now and see if the mouse shape fits better in my hand.