I've used these for awhile. I've got 2 of them now.  It's everything I need from a mouse at this point.  It's extremely accurate, customizable,  fast(although not fast enough that I'd recommend to hardcore gamers), and wireless.  Some have complained about it not being bluetooth, but that's never been a drawback for me.  I can usually get a couple weeks out of the battery with normal daily use.  

  It requires 2 pieces other than the mouse itself.  One plugged into the usb port for connectivity and one plugged into the wall for charging. It would be nice if they could maybe combine...