Please note that I did not buy this mouse from Amazon (it did not arrive in time), but I bought the same model at a nearby computer shop. Even at Amazon's lower price, it's still not worth it.
If you want a cheap mouse, then Amazon has plenty of mice for about half the price of this, and you wouldn't notice any difference between them. The only reason it gets two stars rather than one is because it's quite accurate and doesn't jitter at all - but then again, I doubt it's any better than the cheaper mice on offer here.
The main problem with this mouse is the bad ergonomics - the button-click is flimsy, the side buttons stick out and are easy to press accidentally, and the scroll wheel doesn't 'click' so you end up over-scrolling all the time (and even on the slowest setting, it's far too fast). The wheel also has a 'sideways scroll' function, but since the wheel is almost set flush with the surface of the mouse, it's impossible to use without either scrolling vertically or accidentally pressing one of the side buttons. Worst of all, on the side of the mouse body itself, there's a moulding line right where your thumb sits, which is very annoying. The mouse is far too light for any detailed work. The wheel is also incredibly hard to click for use as a third mouse button, and because it is 'frictionless', it tends to scroll as you click, which is annoying when surfing the internet and totally hopeless when trying to play computer games.
Furthermore, the friction pads on the underside of the mouse making a scratching noise when moved on my wooden desk - I've not experienced this with any other mouse.
If you want a cheap mouse, save a fiver and buy the cheapest one you can find - it won't feel any worse than this one. If you want a performance mouse, spend an extra £10 and get something heavier, better built and better designed.