All in all, for a mouse, it's a good investment at the price. I'd buy it again. It's nice an responsive, perhaps a touch too responsive at times, but that can be tweaked with settings. I'm not a big fan of HAVING to download 3P software for every peripheral.
* 8 Buttons * Fluid switching on responsiveness * Good size for my somewhat large hands * LED isn't intrusive; but nice muted slightly blue glow
* Extremely light - I do prefer a bit more weight or heft to my mouse * Middle click seems to register two inputs with a single click; Probably a setting, but an annoying default; * Had to download the Logitech software to stop the LEDs from doing the annoying "breathing" mode (fade in and fade out)...