The side buttons are well placed, those above, except the last one left at the end which is a bit unreachable by the finger and practices are those of the knob that switches the left and right are good assets. What's great is also the ability to unlock the click of the wheel to make it free and thus rotate with momentum. In short, a great design, a good mouse to the base. But there is a big flaw, as I say, two big flaws ... After a few months of use, the left button is set to stop working, so back to SAV. Then with the new mouse is even after a few months left click also began to no longer function properly. Remember that it is very annoying to have to move such an icon and see the mouse let go anywhere before the end. Same, it is currently almost impossible to select a text box without it loose before it causes or accidental double clicks (bad contact). In short, it is unusable. Best of all, the left tilt wheel, which I use to make the "back" began to stop working for a few days ... In short, the buttons are a very very very bad ... I am very disappointed with that provided me Logitech mouse for 15 years and will now change the brand, which will have buttons that will keep on for normal use because I do not support such a nag me above and is mainly used professionally. My choice was based on the number of programmable buttons.