Here it is defective for a normal use of one year, the microswitch to the left button. After a brief Internet research is apparently not an isolated case. That must be possible for such an expensive Logitech device naturally chalk, but of course exchanges Logitech the device. The support is properly and works perfectly, however, are a few days / weeks without factoring mouse. Who has not a substitute device, quickly has become a problem.
From the price / performance ratio you can now say that it is appropriate. The first device after the presentation were totally overpriced in my opinion, but now it is a very good relationship. Alternative products can be found in the same price range.