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.
Pros Super-accurate, works well on a variety of surfaces, lightweight, silent scrolling, feels comfortable
Cons Batteries drain pretty quickly if you leave your computer on 24-7
Summary I love this mouse. To me, the most important feature of a mouse is precision. If your mouse is erratic or sluggish, it is like driving a Ford Explorer - you feel like you're trying to steer a lump of Jello. If you're mouse is precise, it is like driving a Jetta or an RX-8. The drawback is that the batteries take a beating to keep this precision. Thankfully, there's a tiny power switch on the underside of the mouse. In my own experiences, I haven't found the mouse to go dead quickly, even with the button left on, but it could be because I don't leave my computer turned on all night long. (I suspect the mouse has some kind of feature to go dormant when it senses no signal coming from the USB Bluetooth transceiver.) I'm not sure about this, but I think the extraordinary precision is the result of two factors. Firstly, the mouse uses Bluetooth to communicate. (As long as you're not near a microwave or anything else that can disrupt Bluetooth, you're good to go.) Secondly, the sensor mechanism on the underside of the mouse seems to be built with a larger pick-up area. The hole is quite large and the LED is quite a bit brighter (and different color, blue instead of red) than most other wireless mice. The mouse works on many different surfaces, including on my molded white plastic table, on a shiny granite counter top, and even on glass. (The only times that I was able to trip the mouse up were by using it sideways on a clear window, or on a mirror.) I've occasionally experienced stray airborne cat hair accumulating in the sensor hollow, which I sweep out with a few brushes with my finger. I hardly ever use a scroll wheel, but when I do, I'm pleased with the smooth, almost silent scrolling of this mouse. The mouse is small but not too small, and is comfortable in my hands as well as my aunt's smaller hands. I'm puzzled why the posters of Jan 11, 2010 and Dec 3, 2010 had such trouble with this mouse. I haven't experienced any of the things that they mentioned. I recommended this mouse to everyone in my family.Update: This mouse uses a blue LED and 2.4 GHz frequency. I'm not sure anymore if it's actually using Bluetooth, or if it's using a proprietary technology with similar frequency. I saw "blue" in BlueTrack, and I know Bluetooth uses frequencies between 2400 and 2484 MHz, so I assumed BlueTrack was based on Bluetooth.
Updated on Apr 17, 2011
Pros Comfortable, nicely customizable. I like smooth scrolling. USB nub is very short so I leave it in ALL the time and it's never in the way. Great price. If it gets 6 months battery instead of 9, who cares, it's one AA, what like 89c? Looks great.
Cons When I power it off to save battery (nicely easy to do) because the USB dongle is still attached, the track-pad does not automatically re-enable. Since this is very rare, not a problem.
Summary Happy with my choice, based on CNET review, Dec 2013. I paid $24 at Staples, can't beat that.
Pros Very smooth scroll, atractive design.
Cons Battery wont last near 3 months. I have owned this mouse for approx. 6 months and have had to change the battery twice already meaning the mouse has used 3 batteries counting one that came in the package. Average life for each: 2 months, 8 hr/day
Summary Doesnt deliver on 10 month promise. Not satisfied with product, the mouse is also not confortable with big handed users.
Pros Great design and feel
Cons Unable to use on all surfaces!
Summary Thinking this was a good mouse I purchased it, found that it does not work on all surfaces! I have a large calendar on my desk and it will not work properly on it either... Maybe I have a defective one?! Very disappointed.