This is, without doubt, the best mouse I have ever owned.

It is comfortable, responsive, and its most important feature, hugely customizable.

While the £70 I paid for it is certainly a lot of money, it was very well spent. I have used this mouse almost every day for the 2+ years I have had it, and I now dislike using any other mouse.

The mouse wheel is incredible, and quite rightly emphasized by all of the reports about it. When using spreadsheets, word document, websites, games, etc it can scroll at an incredible rate. If I want to scroll to the bottom of a huge spreadsheet, I can do it with ease. I just quickly tested, and with 1 quick spin I can fly through 100,000 excel rows. Just one spin..

With such a fast speed you may be worried about accuracy, however fear not! You can change the type of scrolling from "free spin" to "Click-to-click" which changes the spin type to the same type as a standard mouse. You can change how the mouse spins depending on speed. If I scroll slowly on excel it will stay on "click" mode, but above a certain user-defined rotation speed it will auto switch to "free spin".

You can change what any of the mouse buttons do from a list of options, as far as having the option to input multiple key press such as "Ctrl + C". This is extremely useful for working with documents and also in games where I can map different commands to different buttons.

The customization doesn't stop there however. You can select a different set of button settings depending on what program you are working on. In word I want to have Copy, Paste, Page Down and Page Up mapped to my side buttons, but when I switch to my internet browser I now want Forward, Back, New Tab and Switch Tab. The Logitech software automatically detects which program you are using and loads your specific button settings immediately.

The amount you can customize the setting of this mouse brings its only downside as far as I can see. It can be quite confusing and time-consuming to set up all your program button definitions. While you can set just a base configuration and leave it at that (all programs will use the base configuration as default and only switch to another if you have defined it specifically) that does limit the functions of the mouse. For anyone who is pretty computer savvy will have no problem however.

A full charge of the on-board battery will lasts for 2-3 days of heavy use, and most likely a week of occasional use. Charging is done via a neat little docking station that sits on your desk and plugs into the mains.

Connection is wireless, with a small USB receiver. Range is not huge at around 2 metres, so you cant use it as a remote from the other side of the room.