I've owned one for four months now. Took some getting used to in the first couple of days, but now I couldn't game without it. Love the fact that it stores profiles and settings in it's memory, and they are available for use on any machine without the need to install the Logitech software.
Over the years from a Sidewinder X8, through a couple Razers, a Corsair Vengeance M95, and onto this. The Logitech G600 is the best mouse I have ever touched. The perfect size and heft for my hand, the ring finger button, and the 12 thumb buttons make this the perfect mouse for any game or gaming style.