I had spotted a curious tendency for the pointer to 'jump' to random points on the screen from time to time, but found it to be a feature of the mousing surface I was using. Use too-shiny a mousemat and the optical detector picks up false reflections and can make it think the mouse has moved a significant distance. Keep the alcove clear of dust and use a fabric surface to 'mouse' on and it should be fine.
Overall a good little mouse and one that I enjoy using for high-speed games without complication.
I found, to begin with, that my hand (of average size, maybe longer fingers) got stiff using this mouse for extended (> 4 hours or so) periods. There is also slight dark discolouration on the main two mouse buttons where dirt has rubbed on and this won't shift. But this is only very slight. The side back/forward buttons' icons are scratching off too. I've had this mouse since early June.
Other than that I use this mouse on a semi-shiny desk surface and have no skipping problems and I find the extra buttons extremely useful. I use the back/forward buttons for back/close window, the top button assigned to F9 for Exposé and the scroll wheel button as command-click, which opens up pages in a new tab when browsing on the Internet. This is a great set up. Good functionality from the mouse.