It is very precise with a plethora of customisable button functions but the upper side buttons (you can see one on the upper left on the picture of the mouse, a small silver slither, & there is another one on the opposite side), are so easily hit when using the mouse, which causes functions to happen, made for an very unhappy start for myself.
To save my sanity from continually having to close the magnifying glass etc when I inadvertantly hit the button, I have disabled both upper button functions. It works fine now but I have partially defeated the object of buying this mouse by negating some of its functions
This mouse, while very very good, comes with a receiver that is almost as big as the mouse.
Not so good if you have a laptop and were expecting a usb dongle...
Its fine for desktops, and the receiver works very well - its just too bulky to make a good 'carry it around with the laptop' mouse.