Middle-click is a problem
924684
On the positive side, this mouse:
1. Has nice balance once you add the included weights to fit your preference.
2. Has nice movement and scrolling speeds once you install the software and set your preferences.
3. Fits well into your hand once you choose your preferred shell.
4. Tracks well on surfaces where an optical mouse might struggle.

On the negative side:
1. The middle-click button is hard to press, making it almost completely unusable.
2. The bottom of the mouse has pads which actually kind of grab on to some mouse pads. I can't use my mouse pad with this mouse; I have to just use it directly on my desk.

If it weren't for the middle-click problem, this would be a great mouse. But anyone who uses the middle button often should beware. (I am leaning toward returning it because of this.)
137710
Pros:
-I like the angles when I hold the mouse.
-I like the fact that I can move to my left or right hand.

Cons:
- The left click (upper click) is really stiff and I think it bumps into the scroll from time to time, this is really bothering as sometimes left click works and sometimes I have to press it multiple times. It won't be obvious if I were to try it only once or twice, but it comes and goes as I use, and it's irritating...Thus two stars.
- Also, tried pushing scroll a bit lower, and it seems lowering scroll actually gives a click on the scroll (the mouse regards it as the same action as actually clicking the scroll).

Dear Amazon & Posturite:
I thought this can't go wrong and threw out all the boxes and manuals ...
Can I still return this item?
1961610
It's not terrible, but certain design choices are absolutely infuriating. I destroyed my mouse (intentionally) after too many times of it screwing up in the middle of something important. If you let it sit for several minutes it goes to sleep where it won't do anything when you move it, so you have to click a button to reactivate it. But rather than that click *ONLY* reactivating the device, it does actually click wherever the mouse happens to be on your screen at the time. So if you accidentally had the mouse near the "X" button to close your program when it went to sleep, then when you click it to wake it up, it will close your programs. This happened to me multiple, multiple times. And after losing work or closing important internet tabs I was in the middle of, I just smashed the mouse and bought a new one of a different brand. I have never had this particular issue with other mouses so it seems like something other brands have figured out a long time ago. Just save your sanity and find a different brand. There are TONS of cheap wireless mice available that don't have this issue.
4513186
Love everything about it except that the scroll wheel is too easy to accidentally scroll when middle clicking in detent mode.
3250905
The mouse is good - I really like the thumb button and horizontal scroll wheel.  There is a problem with the software, though - the thumb wheel and forward/back buttons only work intermittently.  I will be working on a large spreadsheet, happily scrolling sideways, and it will just stop, and not work for several minutes, then it will start working again with no indication of why.  It is only the "extra" functions that have this problem, though - "regular buttons and scroll wheel always work.  I like the smart scroll function, too - took some getting used to, but now that i get it, it works well.
1352444
I've purchased two because of a broken MB1 (left click), would double click whenever held down (full auto in a FPS would stop sporadically, highlighting things).  Same issue happened w/in 6 months of purchasing both.  I tend to pick the mouse up and put it back down a lot due to a small mouse pad.  I want to say that's why I've had this issue; so if you pick your mouse up while playing, maybe check out some other options.
3710680
Middle thumb wheel used for scrolling is too sensitive. The wheel also acts as a "middle button" when pressed; but, when scrolling, it is very difficult to avoid pressing it.  The middle button press sends the mouse into a funny (totally different) scroll mode.  It's just plain annoying. The middle button behavior cannot be changed (nor can ANY of the buttons) and the button cannot be disabled.  Problem is the MS Intellimouse software, which normally would give you a way to disable/change the button behavior, does not support this mouse (some problem with the design of the mouse and can't be "fixed").

Had I known this, I never would have purchased it.  It borders on unusable.
3201647
The mouse range is too easily interfered by monitors. I have been using a wireless Logitech mouse for a while and decided to try a keyboard/mouse combo. After installation, the mouse range is less 6" since I placed the receiver on top of the monitor. Once the receiver was placed away from the monitor, it works just fine. Even worse is that the receiver cable cannot be close to the monitor cable! And since I am using a KVM switch, the receiver cable WILL have to be close the monitor cable. This renders the combo set useless. In contrast, the Logitech mouse has no problem at all with the monitor and the reponse time is even better. What a disappointment!

Also beware of the middle mouse button. If your application uses middle button for zoom or other functions, this mouse does not perform at an acceptable level. It needs to be clicked very carefully to function as a middle button, terribly annoying. It is mostly likely caused by the tilting function. If you do 3-D modeling and use the middle mouse button a lot, avoid this mouse by all means.

Another thing I noticed is that microsoft's products seem only to work well with windows! Other brands I tried don't have this issue at all, such as Logitech, A4 Tech and Belkin. They simply perform as they promised. Microsoft's mouse usually has issues on the middle mouse button - either not reponding or slow, especially for Linux systems.
506059
I had a pc with the usual mice, and then my new imac arrived with the Mighty Mouse.  I was attempting to be open-minded as I programmed the right button to work like it does in Windows - except that because of the shape of the mouse and how I hold it, I seem to always get right button features when I want left.  It is very difficult to constantly remind myself to move my fingers over.

But WORST of all is the scroll button.  I wouldn't mind if it was just small and cheap, but it doesn't work.  Yes, I have been all over the Internet looking at ways to clean it, and sometimes the methods work, but it ultimately clogs back up within just a few hours -- sometimes just a few minutes.  It is completely exasperating and I can't believe that Apple would create such a creature that makes me want to throw it out the window.  If it worked, I might recommend it.  But it doesn't.
1993502
I would normally assume this was just a bad mouse. But, I see others have had the same problem. The middle mouse button/wheel stopped working for the button function. The wheel still works. It clicks, but does not get treated as a middle mouse button click anymore. I checked on another machine - not a SW or OS problem. Otherwise it would have been a great mouse.
402959
I'm still learning how to use windows 8. It's just too many clicks to shut down. It took me a while to figure out how to turn it off.
4351228
As stated in many of the reviews, you'll love it or hate it. I appreciated the sleek design and minimalist approach. Just because it doesn't look or feel like others mice I'm used to does not mean it is inherently bad. I had no problems having an intuitive interaction with the product. I actually liked the way it felt in my hand, scrolling was very smooth and the next/back swipe control is great. But unfortunately this product has one critical fault I can't overlook.

The major pitfall for this device is the absence of middle click (aka. mouse 3, mouse wheel click). I really wish I had studied more before purchasing, as it is mentioned in several reviews. Hopefully one more will help the next guy.

I do lots of CAD work in a Linux environment and mouse 3 is a common control used for panning or tilting. Without it, well, I cant work without it.

Some people will reply to this jabbering about SetPoint software (provided by logitech) allowing additional features, but this is nonsense.
- Middle click has been a standard feature in mice for a decade or more and shouldn't require additional resources from my computer.
- SetPoint is windows only. No Linux/Mac support. So no luck for me.

Back it goes. Dang, I liked this one.
4114918
After a few weeks, the middle button on the mouse (scroll button) has completely stopped responding. It seems that this is a recurring problem with logitech mice, going back to at least 2005 [...]. I have tried the standard options (looked for drivers updates, looking at under Control Panel settings, windows troubleshooting) and unfortunately they have not helped.
2662010
They should make you aware of it, maybe show a "map" of the keys.
The "delete" button as well as some other buttons are located in places my fingers are not used to which often makes me go back and correct myself. Also makes it hard to press CTRL-ALT-DEL
2924473
I got this mouse to increase the number of buttons available while playing MMOs. When I first got the mouse I had trouble adapting to the very light pressure needed for the left and right buttons -- I was always clicking things accidentally. I also had problems accidentally pressing the "shift" button instead of the right mouse button.

I got used to that in a couple of days so those were just temporary nits. The real problem is that the thumb buttons -- the reason I got the mouse in the first place -- require much more pressure to activate. To click them you have to push much, much harder than you have to click the left and right buttons, which means that when you try to click the thumb buttons you wind up clicking the left or right button as well since you need to hold the mouse somewhere. Theoretically I should be able to squeeze the mouse with my little finger while I press a button with my thumber, but I find that very clumsy.

This wouldn't be a problem if all the buttons on the mouse required the same light touch, but the greater pressure required for the thumb buttons leaves me dissatisfied.
4200739
Middle scroll mouse button is entirely erratic. Sometimes the page scrolls, but mostly it just twitches like it's having a seizure. Other mouse buttons work fine, and it's decent for gaming and regular use. At this point, I would not buy from this maker again.
4388778
I enjoy the side buttons, but the middle mouse button shorted out and is now unsuable. Luckily the software for the mouse lets me rebind that button.