"Unresponsive and jerky"2.0 starson by Villnius
Pros: -Battery compartment has a pull tab. Took Microsoft a very long time to add this feature. It makes removing the battery easier
-Comfortable. It's large for a mobile mouse, which might be good or bad
Cons: -Jerky and unresponsive. Frequently gets jerky and freezes (old model 2000 wireless is much more responsive and reliable)
-absolutely rubbish manual. Documentation is 3 pieces, in multiple languages. Only one page is actually about this mouse.
Summary: I had bought this to replace an aging Microsoft wireless 2000 mouse. That was an old full size wireless optical mouse with the old hockey puck transceiver. Main reason what that it didn't have the precision I was looking for.
Too bad that old work horse runs rings around this piece of crap. The Mobile Wireless 4000 regularly stutters, slows down and sometimes just freezes for long periods, making it absolutely worthless as a mouse. The old 2000 model never had this problem and it was an RF wireless as well. The mini-dongle also doesn't have the range of the old hockey puck style that the 2000 uses. The stuttering, and freezing just gets worse if you move it more than a meter away from the dongle. The old hockey puck on the 2000 will receive and function from across the room (4 meters away).
On the plus side, Microsoft finally put a pull tab in the battery compartment so that you can easily remove the battery (and the 4000 only requires ONE). On the old 2000, once you slide in the batteries, the battery compartment's hatch wasn't really big enough to get the batteries out easily, and there was no pull tab to help you. This alone isn't enough to warrant the purchase because ultimately, you'd want to buy this because you need a mouse -- to move the pointer around your screen and interact with the OS or games. This paperweight just can't do that reliably.
Finally, the manual is a useless waste of paper. There's 2 pamphlets and a one sheet quick start guide. Only that one sheet quick start guide even mentions anything specific to the mouse and it basically only tells you where to stick the battery and the transceiver dongle. That's it. One's a thick booklet of legalese detailing the warranty in several languages. The other booklet is a very generic "product guide" that is about as relevant to this device as the instruction manual for a DVD player. It barely even mentions computer mice at all, and only in general terms. If they were going to kill a tree, I'd have preferred it if they actually devoted most of the paper to actually telling me about the mouse I just bought.