Ultimately, mouse-users of the world can be divided into two categories. Those who need or want 13.2 billion configuration options, and those who don't. The former group are almost exclusively gamers, and for them, £40 is actually a decent price for this mouse and what it offers.
If you prefer to keep things simple, and don't want a massive great big bit of plastic on your desk, then there are other, more stripped-down, more attractive options, that offer just as much in terms of comfort and performance. But just think of all the different configurational choices you'll be missing out on.
If gaming is your thing and the PC is your king then the Logitech G9 is your one stop destination for gaming domination. It's well designed, well featured and incredibly versatile and as such comes highly recommended.
(Les notes de la presse sont données à titre indicatif et représentent une interprétation du test par Numerama)