I own the MX 1100 and am quite satisfied, unfortunately now happen the left mouse button does not always work correctly with the mouse. So I decided the MX Performance test and thought at first that it is very similar to the MX1100, which unfortunately is not the case. Negative points: -Liegt Not well in the hand and is too small (187cm) -The XButtons are difficult to reach or the distance is too far. -The Push button interferes and nessesary too much pressure, you slip a hand on the mouse -The Wheel is schwamig and the left-right scrolling function without clicking ^^ -The Mouse button clicks are too loud for me what is a little but negligible. -When Pressing the thumb button, the material is expressed wech and opens onto a plastic edge