I've got mine, really like the movement on the trackball, its quite nice to use.
However, there is a slight issue where like 25% of the rotation of the scroll wheel isn't picked up.. . this gives a very jumping, bursty feeling to the scroll, which is rather annoying.
Anyone else experiencing that>
DaankMeemslmao late answer, but the issue is most likely some junk on the parts that register the movement or whatever. Just open it up and get rid of dust etc