I am also using MX1000 and I too have some problems but not as severe as yours. In my case the cursor stutters when I move around poser and cause me to click on the wrong items or lose track of it. I am not sure what exactly is causing this but seems to happen randomly. This is a bluetooth version but I also had similar problem with the their older wireless optical version that I upgraded from. I've tried using the latest driver, using different usb/serial port, using without their setpoint software, fresh install of the system, and none seems to fix this problem. One thing that you might wanna try is to disable the "enhance pointer precision" under mouse option using the mouse properties in control panel.

Only reason I've stuck with the logitech is because their mouse has more buttons and was hoping that the bluetooth version somehow fixed this problem but I guess I am cursed from using their product. I also use microsoft explorer optical wireless and it works fine like it should. My only gripe with it is I wish it had few more buttons which I became very accustomed to using with the logitech. But, regardless, I think I am done with using logitech mouse ever, their keyboard on the other hand... :)