I think I just bought a usb version of one of these at a thrift store for two bucks. Been using it at work, and compared to a Model M I was using it was a little hard to get used to. The mouse pad is handy as hell, but the only tactile feeback was bottoming out on the board. It's better for Quakelive than the Model M/F, but for everyday use, I might go back to the space saver M I was using.