Comment Consider your surroundings (Score 1) 519
For the longest time, I've searched for a decent left-handed ergonomic mouse. Well, I settled on the Logitech MX-610. It has a little proprietary 2.4GHz dongle. I found the mouse to be horribly jerky in movement, the pointer jumps, button clicks sometimes just don't respond. I found to solve this I had to use an USB extension cord and keep the receiver TAPED to the side of the mouse (losing the 'ergonomics' of the mouse itself). I called Logitech and they said I had a faulty dongle.
They shipped me an entirely new package -- mouse, dongle, manual, the whole retail package (FANTASTIC customer support!!) however, I had the same problem. I found it was my wireless router in the other room. I've got four computers that are wireless and a Playstation 3 using WiFi. When there is NO network traffic, the mouse works perfectly!
So, keep that in mind. If you're using all 5GHz stuff, you should be fine. In my case, I have a couple of PDAs that I use that are 802.11b only. But be mindful of your router!!