If there was such a thing as the Gaming Mouse Hall of Fame, the Logitech MX518 would be the first inductee. It's the Jerry Rice of gaming mice, if you'll pardon the odd analogy. Its phenomenal performance in-game, unmatched reliability, and untouchable reputation make it the first choice among veteran PC gamers.
So you might be pulling your hair out upon hearing that Logitech re-designing the MX518, and calling it the G400. Never fear, true believers, as the G400 is as worthy a successor as any mouse could be.
This "redesign" is merely an update, especially from a design point of view. The contours and shape are the same as the MX518...in fact, the G400 packing literally says the G400 is "the new MX518". If you closed your eyes and placed your hand on an old MX518, then the G400, you'll find telling the difference between the two a bit problematic.The G400 maintains the same button layout, with two thumb buttons, two DPI-switching buttons (one above the mouse wheel and one below) and another DPI toggle that resets the sensor to the profile default setting.
Logitech knows better than to mess with perfection, so the real major update is in the sensor. We're still looking at an optical (not laser) sensor, but it's been updated to a 3600dpi model. Chances are you'll never set the mouse to 3600dpi, but the new sensor is accurate, fast, and uniform. The included software makes customization and DPI setup a snap; it's low on tacky color schemes and high on functionality. Switching between DPI settings is great in a number of different games, especially if vehicles are involved. In Battlefield 3, for example, I use my default DPI setting of 1600 for running around on foot, but I dial it down to 1000 or 600 if I hop in a tank or helicopter, or if I decide to use a sniper rifle. A lower DPI helps tremendously if you need to focus on accuracy instead of ultra-quick movement.
The best part about the G400 is the price. Logitech currently lists it at $49.99, and you can find it online for as low as $40. Considering you're getting one of the best gaming mice on the market, that price makes the G400 one of the best values in PC gaming today.