Button wise, there are a few changes. Instead of having two thumb buttons, there is now only one, and although it is larger, I still would have preferred two buttons here, as they come in handy for copy and paste. The scroll wheel is now larger also, and features not only vertical scrolling, but horizontal scrolling as well. A handy feature to have. The increase and decrease sensitivity buttons on the MX518 have been repositioned also. Both of these now reside below the scroll wheel, and there is also a handy light indicator to show which DPI setting is currently selected. Left and right click buttons remain the same - which is excellent!



Looking at the belly of the beast, you'll notice some very significant improvements! The three mouse feet are now much larger than before, and are made of a special polytetrafluoroethylene material that is much smoother than the mouse feet of old. Running the G5 across my Razor eXactMat, I immediately noticed significantly less resistance compared to my old MX518 mouse. Thumbs up again, Logitech.